Processes and intermediates

ABSTRACT

The invention relates to compounds and processes useful for the preparation of protease inhibitors, particularly serine protease inhibitors. The protease inhibitors are useful for treatment of HCV infections.

CROSS-REFERENCE

This application claims priority under 35 U.S.C. 119(e) to U.S. Ser.Nos. 60/709,964, filed Aug. 19, 2005, and 60/810,042, filed Jun. 1,2006, each of which is incorporated herein in its entirety.

FIELD OF THE INVENTION

This invention relates to processes and intermediates for thepreparation of protease inhibitors, in particular, serine proteaseinhibitors.

BACKGROUND OF THE INVENTION

Infection by hepatitis C virus (“HCV”) is a compelling human medicalproblem. HCV is recognized as the causative agent for most cases ofnon-A, non-B hepatitis, with an estimated human sero-prevalence of 3%globally (A. Alberti et al., “Natural History of Hepatitis C,” J.Hepatology, 31 (Suppl. 1), pp. 17-24 (1999)). Nearly four millionindividuals may be infected in the United States alone. (M. J. Alter etal., “The Epidemiology of Viral Hepatitis in the United States,”Gastroenterol. Clin. North Am., 23, pp. 437-455 (1994); M. J. Alter“Hepatitis C Virus Infection in the United States,” J. Hepatology, 31(Suppl. 1), pp. 88-91 (1999)).

Upon first exposure to HCV, only about 20% of infected individualsdevelop acute clinical hepatitis while others appear to resolve theinfection spontaneously. In almost 70% of instances, however, the virusestablishes a chronic infection that may persist for decades. (S.Iwarson, “The Natural Course of Chronic Hepatitis,” FEMS MicrobiologyReviews, 14, pp. 201-204 (1994); D. Lavanchy, “Global Surveillance andControl of Hepatitis C,” J. Viral Hepatitis, 6, pp. 35-47 (1999)).Prolonged chronic infection can result in recurrent and progressivelyworsening liver inflammation, which often leads to more severe diseasestates such as cirrhosis and hepatocellular carcinoma. (M. C. Kew,“Hepatitis C and Hepatocellular Carcinoma”, FEMS Microbiology Reviews,14, pp. 211-220 (1994); I. Saito et. al., “Hepatitis C Virus Infectionis Associated with the Development of Hepatocellular Carcinoma,” Proc.Natl. Acad. Sci. USA, 87, pp. 6547-6549 (1990)). Unfortunately, thereare no broadly effective treatments for the debilitating progression ofchronic HCV.

Compounds described as protease inhibitors, and in particular serineprotease inhibitors, useful in the treatment of HCV infections aredisclosed in WO 02/18369. Also disclosed therein in this publication areprocesses and intermediates for the preparation of these compounds,which lead to racemization of certain steric carbon centers. See, e.g.,pages 223-22. There remains however, a need for economical processes forthe preparation of these compounds.

SUMMARY OF THE INVENTION

In one aspect, the invention provides processes and intermediates forproducing a bicyclic pyrrolidine derivative of Formula 1, which isuseful in producing protease inhibitors.

In Formula 1, R₃ is an acid protecting group which can be removed underacidic, basic, or hydrogenation conditions. Under acidic conditions, R₃is, for example, t-butyl; under basic conditions, R₃ is, for example,methyl or ethyl; under hydrogenation conditions, R₃ is, for example,benzyl.

Another aspect of the invention includes processes and intermediates forthe preparation of a compound of Formula 2, which is also useful inproducing protease inhibitors.

In Formula 2,

R₄ is H, an optionally substituted aliphatic, an optionally substitutedcycloaliphatic, an optionally substituted aryl, an optionallysubstituted aralkyl, or an optionally substituted heteroaralkyl;

R′₄ is H, an optionally substituted aliphatic, an optionally substitutedaryl, an optionally substituted aralkyl or an optionally substitutedheteroaralkyl; and

R′₅ is an optionally substituted aliphatic, an optionally substitutedcycloaliphatic, an optionally substituted aryl, an optionallysubstituted aralkyl, or an optionally substituted heteroaralkyl; or

R′₄ and R′₅ together with the atom to which they are attached may form a3- to 7-membered optionally substituted cycloaliphatic ring.

The processes and intermediates described herein are also useful for aprocess for preparating a protease-inhibiting compound of Formula 3shown below.

Referring to Formula 3,

R₁ is RW—, P₂—, P₃-L₂-P₂—, or P₄-L₃-P₃-L₂-P₂—;

P₂— is

P₃-L₂-P₂ is

P₄-L₃-P₃-L₂-P₂ is

W is a bond, —CO—, —O—CO—, —NR^(X)—, —NR^(X)—CO—, —O—, or —S—;

T is —C(O)—, —O—C(O)—, —NHC(O)—, —C(O)C(O)—, or —SO₂—;

R is H, an optionally substituted aliphatic, an optionally substitutedcycloaliphatic, optionally substituted heterocycloaliphatic, anoptionally substituted aryl, or an optionally substituted heteroaryl;

R₅ is H, an aliphatic, a cycloaliphatic, a heterocycloaliphatic, anaryl, or a heteroaryl; each of which, except for H, is optionallysubstituted with one or more substituents each independently selectedfrom Group J, wherein Group J includes halo, cycloaliphatic, aryl,heteroaryl, alkoxy, aroyl, heteroaroyl, acyl, nitro, cyano, amido,amino, sulfonyl, sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl,sulfamide, oxo, carboxy, carbamoyl, cycloaliphaticoxy,heterocycloaliphaticoxy, aryloxy, heteroaryloxy, aralkyloxy,heteroarylalkoxy, alkoxycarbonyl, alkylcarbonyloxy, and hydroxy;

R₆ is an optionally substituted aliphatic, an optionally substitutedheteroalkyl, an optionally substituted heteroaryl, an optionallysubstituted phenyl; or R₅ and R₆, together with the atoms to which theyare attached, may form a 5- to 7-membered, optionally substitutedmonocyclic heterocycle, or a 6- to 12-membered, optionally substitutedbicyclic heterocycle, in which each heterocycle ring optionally containsan additional heteroatom selected from —O—, —S—, or —NR^(X)—;

Each of R₇ and R₇′ is independently H, an optionally substitutedaliphatic, an optionally substituted heteroalkyl, an optionallysubstituted heteroaryl, or an optionally substituted phenyl; or R₇ andR₇′, together with the atom to which they are attached, may form a 3- to7-membered cycloaliphatic or heterocycloaliphatic ring; or

R₇ and R₆, together with the atoms to which they are attached, may forma 5- to 7-membered optionally substituted monocyclic heterocycle, a 5-to 7-membered optionally substituted monocyclic aryl, a 6- to12-membered optionally substituted bicyclic heterocycle, or a 6- to12-membered optionally substituted bicyclic aryl, in which eachheterocycle or aryl ring optionally contains an additional heteroatomselected from —O—, —S—, or —NR^(X)—; or

When R₅ and R₆ together with the atoms to which they are attached form aring, R₇ and the ring system formed by R₅ and R₆ may form an 8- to14-membered optionally substituted bicyclic fused ring system, whereinthe bicyclic fused ring system may further fuse with an optionallysubstituted phenyl to form an optionally substituted 10- to 16-memberedtricyclic fused ring system;

R₈ is H or a protecting group;

R^(X) is H, aliphatic, cycloaliphatic, (cycloaliphatic)aliphatic, aryl,araliphatic, heterocycloaliphatic, (heterocycloaliphatic)aliphatic,heteroaryl, carboxy, sulfanyl, sulfinyl, sulfonyl, (aliphatic)carbonyl,(cycloaliphatic)carbonyl, ((cycloaliphatic)aliphatic)carbonyl,arylcarbonyl, (araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, (heteroaryl)carbonyl, or(heteroaraliphatic)carbonyl;

R₂ is —(NH—CR₄′R₅′—C(O)—C(O))—NHR₄ or —(NH—CR₄′R₅′—CH(OH)—C(O))—NHR₄;

R₄ is H, an optionally substituted aliphatic, an optionally substitutedcycloaliphatic, an optionally substituted heterocycloaliphatic, anoptionally substituted aryl, an optionally substituted aralkyl or anoptionally substituted heteroaralkyl; and

Each of R′₄ and R′₅ is independently H, an optionally substitutedaliphatic, an optionally substituted cycloaliphatic, an optionallysubstituted heterocycloaliphatic, an optionally substituted aryl, anoptionally substituted aralkyl, an optionally substituted heteroaralkyl,or an optionally substituted heteroaralkyl; or R₄′ and R₅′, togetherwith the atom to which they are attached, may form a 3- to 7-memberedoptionally substituted cycloaliphatic ring.

In some embodiments, the process for preparing compounds of Formula 3includes the step of carboxylation of an azabicyclooctane of formula 6,

wherein R′ is a C₁₋₅ alkyl, to give a racemic mixture of cis- andtrans-octahydrocyclopenta[c]pyrrole-1-carboxylic acids of formula 7.

In some embodiments, each of P₂, P₃ and P₄ is independently a bond, H,an optionally substituted aliphatic, an optionally substituted aryl, anoptionally substituted heteroaryl, an optionally substituted alkoxy, anoptionally substituted alkylsulfanyl, an optionally substitutedaralkoxy, an optionally substituted aralkylsulfanyl, an optionallysubstituted mono- or dialkylamino, an optionally substituted mono- ordiarylamino, or an optionally substituted mono- or diheteroarylamino.

In some embodiments, each of L₂ and L₃ is independently a bond, —C(O)—,or —SO₂—.

In some embodiments, R₅ is a C₁₋₆ alkyl, C₃₋₁₀ cycloalkyl, C₃₋₁₀cycloalkyl-C₁₋₁₂ alkyl, C₆₋₁₀ aryl, C₆₋₁₀ aryl-C₁₋₆ alkyl, C₃₋₁₀heterocyclyl, C₆₋₁₀ heterocyclyl-C₁₋₆ alkyl, C₅₋₁₀ heteroaryl, or C₅₋₁₀heteroaryl-C₁₋₆ alkyl; each of which is optionally substituted with oneto three substituents each independently selected from Group J; and upto three aliphatic carbon atoms in R₅ may be independently replaced by aheteroatom or group selected from O, NH, S, SO, or SO₂, in a chemicallystable arrangement.

In some further embodiments, R₅ is

In some embodiments, R₇′ is H; R₇ is a C₁₋₆ alkyl, C₃₋₁₀ cycloalkyl,C₃₋₁₀ cycloalkyl-C₁₋₁₂ alkyl, C₆₋₁₀ aryl, C₆₋₁₀ aryl-C₁₋₆ alkyl, C₃₋₁₀heterocyclyl, C₆₋₁₀ heterocyclyl-C₁₋₆ alkyl, C₅₋₁₀ heteroaryl, or C₅₋₁₀heteroaryl-C₁₋₆ alkyl; and R₁ is optionally substituted with one tothree substituents each independently selected from Group J; and up tothree aliphatic carbon atoms in R₁ may be replaced by a heteroatom orgroup selected from O, NH, S, SO, or SO₂ in a chemically stablearrangement.

In some further embodiments, R₇ is

In still some further embodiments, R₇ and R₇′, together with the atom towhich they are attached, form

In some embodiments, R is a C₆₋₁₀ aryl, C₆₋₁₀ aryl-C₁₋₁₂ aliphatic,C₃₋₁₀ cycloalkyl, C₃₋₁₀ cycloalkenyl, C₃₋₁₀ cycloalkyl-C₁₋₁₂ aliphatic,C₃₋₁₀ cycloalkenyl-C₁₋₁₂ aliphatic, C₃₋₁₀ heterocyclyl, C₃₋₁₀heterocyclyl-C₁₋₁₂ aliphatic, C₅₋₁₀ heteroaryl, or C₅₋₁₀heteroaryl-C₁₋₁₂ aliphatic; each of which is optionally substituted withone to three substituents each independently selected from Group J.

In some further embodiments, R is

In still some further embodiments, R is

In yet still some further embodiments, R is

and R₁₀ is H, C₁₋₁₂ aliphatic, C₆₋₁₀ aryl, C₆₋₁₀ aryl-C₁₋₁₂ aliphatic,C₃₋₁₀ cycloalkyl, C₃₋₁₀ cycloalkenyl, C₃₋₁₀ cycloalkyl-C₁₋₁₂ aliphatic,C₃₋₁₀ cycloalkenyl-C₁₋₁₂ aliphatic, C₃₋₁₀ heterocyclyl, C₃₋₁₀heterocyclyl-C₁₋₁₂ aliphatic, C₅₋₁₀ heteroaryl, or C₅₋₁₀heteroaryl-C₁₋₁₂ aliphatic.

In still some further embodiments, R is

In yet still some further embodiments, R is

In some further embodiments, R is

In some embodiments, the carboxylation step in the process for preparingcompounds of Formula 3 includes forming a 2-anion of the compound offormula 6

in the presence of a complexing agent, and then treating the 2-anionwith carbon dioxide to produce a racemic mixture oftrans-/cis-octahydrocyclopenta[c]pyrrole-1-carboxylic acids of formula 7

In some further embodiments, the 2-anion of the compound of formula 6 isprepared by treating the compound of formula 6 with a strong lithiumbase in the presence of a complexing agent and an aprotic solvent.

In still some further embodiments, the base used in preparing the2-anion is sec-butyl lithium.

In still some further embodiments, the complexing agent used inpreparing the 2-anion is tetramethylethylenediamine,tetraethylethylenediamine, tetramethyl-1,2-cyclohexyldiamine, sparteine,or a 3,7-di(C₁₋₆ alkyl)-3,7-diazabicyclo[3.3.1]nonane such as, forexample, 3,7-di(n-propyl)-3,7-diazabicyclo[3.3.1]nonane.

In still some further embodiments, the complexing agent istetramethylethylenediamine, tetraethylethylenediamine,tetramethyl-1,2-cyclohexyldiamine, or 3,7-di(C₁₋₆alkyl)-3,7-diazabicyclo[3.3.1]nonane.

In still some further embodiments, the complexing agent is D-sparteine.

In some embodiments, the trans-/cis- ratio in the racemic mixture ofcompounds of formula 7 is 1 to 2.

In some embodiments, the trans-/cis- ratio in the racemic mixture ofcompounds of formula 7 is 40 to 60.

In still some further embodiments, the trans-/cis- ratio in the racemicmixture of compounds of formula 7 is 1 to 1.

In still some further embodiments, the trans-/cis- ratio is 60 to 40.

In still some further embodiments, the trans-/cis- ratio is 80 to 20.

In still some further embodiments, the trans-/cis- ratio is 90 to 10.

In still some further embodiments, the trans-/cis- ratio is greater than98 to 2.

In some other embodiments, the process for preparing compounds ofFormula 3 further includes equilibrating a trans-/cis- mixture of thecompounds of formula 7

in the presence of a suitable base to produce a predominantly trans-cisracemic acid of formula 8

wherein the trans-/cis- ratio is greater than 80 to 20.

In some other embodiments, the process for preparing compounds ofFormula 3 further includes equilibrating a trans-/cis- mixture of thecompounds of formula 7 in the presence of a suitable base to produce apredominantly trans-cis racemic acid of formula 8 wherein thetrans-/cis- ratio is greater than 90 to 10.

In some other embodiments, the process for preparing compounds ofFormula 3 further includes equilibrating a trans-/cis- mixture offormula 7 in the presence of a suitable base to produce a predominantlytrans-cis racemic acid of formula 8 wherein the trans-/cis- ratio isgreater than 98 to 2.

In some further embodiments, the base used in equilibrating thetrans-/cis- mixture of formula 7 is lithium hexamethyldisilazide,lithium di-isopropylamide, or lithium 2,2,6,6-tetramethylpiperidide.

In some further embodiments, the base is lithium hexamethyldisilazide.

In some further embodiments, the base is sec-butyl lithium and thecomplexing agent is 3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane to give amixture of racemictrans-/cis-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylicacids of formula 7, in which the trans-/cis- ratio is greater than 90 to10.

In some further embodiments, thetrans-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acidis trans-N-t-butoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylicacid.

In some other embodiments, the process for preparing compounds ofFormula 3 further includes resolving racemictrans-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acidto produce a(1S,2S,3R)trans-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylicacid.

In some further embodiments, the resolution of a racemic mixture ofcompounds includes the steps of i) forming a salt with an opticallyactive base; and ii) crystallizing the salt formed by step i) to providean optically active salt of formula 9.

In some further embodiments, the optically active base used in resolvinga racemic mixture of compounds is (R) α-aminoethylbenzene.

In some further embodiments, the optically active base is (S)1,2,3,4-tetrahydro-1-naphthylamine.

In some further embodiments, the process for preparing compounds ofFormula 3 further includes the steps of esterifying the caboxylic acidof formula 9 with a compound containing the R₃ group; and removing the—COOR′ protecting group to produce a compound of Formula 1,

wherein R₃ is an optionally substituted alkyl or aralkyl.

In still some further embodiments, R₃ is t-butyl.

In some embodiments, the process for preparing compounds of Formula 3further includes reacting the amino-ester of Formula 1 with R₁COOH inthe presence of a coupling reagent to produce a compound of Formula 1a.

In some embodiments, the reaction between the amino-ester of Formula 1and R₁COOH can be carried out further in the presence of histamine,glycine, or lysine, in addition to a coupling agent.

In some further embodiments, R₁ is P₂—.

In some further embodiments, R₁ is P₃-L₂-P₂—.

In some further embodiments, R₁ is P₄-L₃-P₃-L₂-P₂—.

In some further embodiments, R₁ is RW—.

In some embodiments, the process for preparing compounds of Formula 3further includes the steps of hydrolyzing the ester of a compound ofFormula 1a; to provide a carboxylic acid and reacting the carboxylicacid thus obtained with a compound containing the R₂ group, wherein R₂is —(NH—CR₄′R₅′—CH(OH)C(O))—NHR₄, in the presence of a coupling reagentto produce the compound of Formula 3.

In some further embodiments, R₄ is H, an optionally substitutedaliphatic, optionally substituted cycloaliphatic, an optionallysubstituted aryl, an optionally substituted heteroaryl, an optionallysubstituted aralkyl, or an optionally substituted heteroaralkyl;

R₄′ is H, an optionally substituted aliphatic, an optionally substitutedaryl, an optionally substituted aralkyl, or an optionally substitutedheteroaralkyl; and

R₅′ is H, an optionally substituted aliphatic, an optionally substitutedcycloaliphatic, an optionally substituted aryl, an optionallysubstituted aralkyl, or an optionally substituted heteroaralkyl; or

R₄′ and R₅′, together with the atom to which they are attached, form a3- to 7-membered optionally substituted cycloaliphatic ring.

In some further embodiments, R₂ is

The invention further relates to a process for preparing a compound ofFormula 4

In some embodiments, the process for preparing compounds of Formula 4includes the steps of:

i) providing an N-alkoxycarbonyl-3-azabicyclo[3.3.0]octane;

ii) forming a 2-anion of the N-alkoxycarbonyl-3-azabicyclo[3.3.0]octanein the presence of a chelating agent;

iii) treating the anion of step ii) with carbon dioxide to produce acis-/trans- mixture ofN-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acids;

iv) treating the mixture of step iii) with a strong base to produce anessentially puretrans-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acid;

v) forming a salt of the carboxylic acid with an optically active amine;

vi) crystallizing the salt;

vii) esterifying the salt provided in step vi);

viii) removing the N-alkoxycarbonyl group to produce(1S,3aR,6aS)-t-butyl-octahydrocyclopenta[c]pyrrole-1-carboxylate,t-butyl ester;

ix) reacting the bicyclic of step viii) with a protected amino acid offormula 26,

wherein Z is an amine protecting group, in the presence of a couplingreagent, to produce an amide-ester of formula 27;

x) removing the protecting group Z from the amide-ester of step ix) toproduce the amino compound of formula 28;

xi) reacting the amino compound of formula 28 with a protected aminoacid of formula 29

in the presence of a coupling reagent to produce a tripeptide of formula30;

xii) removing the protecting group Z in the tripeptide of Formula 30 toproduce a free amino-tripeptide of formula 31;

xiii) reacting the amino-tripeptide of formula 31 withpyrazine-2-carboxylic acid in the presence of a coupling reagent toproduce an amide-tripeptide ester of formula 33;

xiv) hydrolyzing the ester of the amide-tripeptide ester of formula 33to produce an amide-tripeptide acid of formula 34;

xv) reacting the amide-tripeptide acid of formula 34 with anaminohydroxy-amide of formula 18

in the presence of a coupling reagent to produce a hydroxy-tetrapeptideof formula 35; and

xvi) oxidizing the hydroxy group of formula 35 to produce the compoundof Formula 4.

In some embodiments, the oxidizing reagent used in step xvi) describedabove is sodium hypochlorite, and the oxidation is carried out in thepresence of 2,2,6,6-tetramethylpiperidinyloxy free radical (TEMPO).

In some other embodiments, the oxidizing reagent used in step xvi)described above is1,1-dihydro-1,1,1-triacetoxy-1,2-benzoiodooxol-3(1H)-one.

In some further embodiments, the process further includes dissolving thecompound of Formula 4 in an organic solvent to obtain its solution, andthen adding an acid to the solution. A suitable organic solvent can beany solvent in which the compound of Formula 4 dissolves, e.g.,methylene chloride. The acid can be any acid, inorganic or organic,e.g., acetic acid or propionic acid.

In still some further embodiments, the process further includesconcentrating the solution of the compound of Formula 4 to obtain thecompound in a solid form. Such a concentrating process can be, e.g.,distillation of the solvent under reduced pressure (e.g., vacuum) bynatural evaporation of the solvent. The solid form in which the compoundof Formula 4 is obtained can be, e.g., crystalline or semicrystalline,and can be of higher purity than that before being dissolved into anorganic solvent and then concentrated in acid condition.

As such, the invention also relates to a process of purifying thecompound of Formula 4.

In some embodiments, the process includes first dissolving the compoundof Formula 4 in an organic solvent to obtain its solution, adding anacid to the solution of the compound of Formula 4, and thenconcentrating the solution of the compound of Formula 4 to obtain thecompound in a solid form. Examples of suitable organic solvents, acids,and solid forms have been provided above.

The invention further features compounds of Formula 1a,

Wherein R₁ is P₂—;

P₂— is

R₅ is H, an aliphatic, a cycloaliphatic, a heterocycloaliphatic, anaryl, or a heteroaryl; each of which, except for H, is optionallysubstituted with one or more substituents each independently selectedfrom Group J consisting of halo, cycloaliphatic, aryl, heteroaryl,alkoxy, aroyl, heteroaroyl, acyl, nitro, cyano, amido, amino, sulfonyl,sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfamide, oxo,carboxy, carbamoyl, cycloaliphaticoxy, heterocycloaliphaticoxy, aryloxy,heteroaryloxy, aralkyloxy, heteroarylalkoxy, alkoxycarbonyl,alkylcarbonyloxy, and hydroxy;

R₆ is an optionally substituted aliphatic, an optionally substitutedheteroalkyl, an optionally substituted heteroaryl, an optionallysubstituted phenyl; or R₅ and R₆, together with the atoms to which theyare attached, may form a 5- to 7-membered, optionally substitutedmonocyclic heterocycle, or a 6- to 12-membered, optionally substitutedbicyclic heterocycle, in which each heterocycle ring optionally containsan additional heteroatom selected from —O—, —S—, or —NR^(X)—;

R^(X) is H, aliphatic, cycloaliphatic, (cycloaliphatic)aliphatic, aryl,araliphatic, heterocycloaliphatic, (heterocycloaliphatic)aliphatic,heteroaryl, carboxy, sulfanyl, sulfinyl, sulfonyl, (aliphatic)carbonyl,(cycloaliphatic)carbonyl, ((cycloaliphatic)aliphatic)carbonyl,arylcarbonyl, (araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, (heteroaryl)carbonyl, or(heteroaraliphatic)carbonyl;

R₈ is H or a protecting group; and

R₃ is an optionally substituted alkyl.

In some embodiments, R₃ is t-butyl.

In some other embodiments, P₂— is

In some further embodiments, P₂— is

The invention further relates to compounds of Formula 1a show above, inwhich

R₁ is P₃-L₂-P₂—;

P₃-L₂-P₂— is

R₅ is H, an aliphatic, a cycloaliphatic, a heterocycloaliphatic, anaryl, or a heteroaryl; each of which, except for H, is optionallysubstituted with one or more substituents each independently selectedfrom Group J consisting of halo, cycloaliphatic, aryl, heteroaryl,alkoxy, aroyl, heteroaroyl, acyl, nitro, cyano, amido, amino, sulfonyl,sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfamide, oxo,carboxy, carbamoyl, cycloaliphaticoxy, heterocycloaliphaticoxy, aryloxy,heteroaryloxy, aralkyloxy, heteroarylalkoxy, alkoxycarbonyl,alkylcarbonyloxy, and hydroxy;

R₆ is an optionally substituted aliphatic, an optionally substitutedheteroalkyl, an optionally substituted heteroaryl, an optionallysubstituted phenyl; or R₅ and R₆, together with the atoms to which theyare attached, may form a 5- to 7-membered, optionally substitutedmonocyclic heterocycle, or a 6- to 12-membered, optionally substitutedbicyclic heterocycle, in which each heterocycle ring optionally containsan additional heteroatom selected from —O—, —S—, or —NR^(X)—;

R₇ is H, an optionally substituted aliphatic, an optionally substitutedheteroalkyl, an optionally substituted heteroaryl, or an optionallysubstituted phenyl; or

R₇ and R₆, together with the atoms to which they are attached, may forma 5- to 7-membered optionally substituted monocyclic heterocycle, a 5-to 7-membered optionally substituted monocyclic aryl, a 6- to12-membered optionally substituted bicyclic heterocycle, or a 6- to12-membered optionally substituted bicyclic aryl, in which eachheterocycle or aryl ring optionally contains an additional heteroatomselected from —O—, —S—, or —NR^(X)—; or

When R₅ and R₆ together with the atoms to which they are attached form aring, R₇ and the ring system formed by R₅ and R₆ may form an 8- to14-membered optionally substituted bicyclic fused ring system, whereinthe bicyclic fused ring system may further fuse with an optionallysubstituted phenyl to form an optionally substituted 10- to 16-memberedtricyclic fused ring system;

R^(X) is H, aliphatic, cycloaliphatic, (cycloaliphatic)aliphatic, aryl,araliphatic, heterocycloaliphatic, (heterocycloaliphatic)aliphatic,heteroaryl, carboxy, sulfanyl, sulfinyl, sulfonyl, (aliphatic)carbonyl,(cycloaliphatic)carbonyl, ((cycloaliphatic)aliphatic)carbonyl,arylcarbonyl, (araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, (heteroaryl)carbonyl, or(heteroaraliphatic)carbonyl;

R₈ is H or a protecting group; and

R₃ is an optionally substituted alkyl.

In some embodiments, R₃ is t-butyl.

In some embodiments, P₃-L₂-P₂— is

In some embodiments, P₃-L₂-P₂— is

Also within the scope of the present invention are the compounds of3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane, and3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonan-9-one.

DESCRIPTION OF THE INVENTION I. Definitions

For purposes of this invention, the chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 75^(th) Ed. Additionally, generalprinciples of organic chemistry are described by Thomas Sorrell inOrganic Chemistry, University Science Books, Sausalito (1999), and by M.B. Smith and J. March in Advanced Organic Chemistry, 5^(th) Ed., JohnWiley & Sons, New York (2001), the entire contents of which are herebyincorporated by reference.

As described herein, compounds of the invention may optionally besubstituted with one or more substituents, such as are illustratedgenerally above, or as exemplified by particular classes, subclasses,and species of the invention.

As used herein the term “aliphatic” encompasses the terms alkyl,alkenyl, and alkynyl, each of which is optionally substituted as setforth below.

As used herein, an “alkyl” group refers to a saturated aliphatichydrocarbon group containing 1-8 (e.g., 1-6 or 1-4) carbon atoms. Analkyl group can be straight or branched. Examples of alkyl groupsinclude, but are not limited to, methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-heptyl, or2-ethylhexyl. An alkyl group can be substituted (i.e., optionallysubstituted) with one or more substituents selected from the group J(“Group J”) which consists of halo, cycloaliphatic (e.g., cycloalkyl orcycloalkenyl), heterocycloaliphatic (e.g., heterocycloalkyl orheterocycloalkenyl), aryl, heteroaryl, alkoxy, aroyl, heteroaroyl, acyl(e.g., (aliphatic)carbonyl, (cycloaliphatic)carbonyl, or(heterocycloaliphatic)carbonyl), nitro, cyano, amido (e.g.,(cycloalkylalkyl)carbonylamino, arylcarbonylamino, aralkylcarbonylamino,(heterocycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, heteroaralkylcarbonylamino alkylaminocarbonyl,cycloalkylaminocarbonyl, heterocycloalkylaminocarbonyl,arylaminocarbonyl, or heteroarylaminocarbonyl), amino (e.g.,aliphaticamino, cycloaliphaticamino, or heterocycloaliphaticamino),sulfonyl (e.g., aliphatic-SO₂—), sulfinyl, sulfanyl, sulfoxy, urea,thiourea, sulfamoyl, sulfamide, oxo, carboxy, carbamoyl,cycloaliphaticoxy, heterocycloaliphaticoxy, aryloxy, heteroaryloxy,aralkyloxy, heteroarylalkoxy, alkoxycarbonyl, alkylcarbonyloxy, andhydroxy. Without limitation, some examples of substituted alkyls includecarboxyalkyl (such as HOOC-alkyl, alkoxycarbonylalkyl, andalkylcarbonyloxyalkyl), cyanoalkyl, hydroxyalkyl, alkoxyalkyl,acylalkyl, aralkyl, (alkoxyaryl)alkyl, (sulfonylamino)alkyl (such as(alkyl-SO₂-amino)alkyl), aminoalkyl, amidoalkyl, (cycloaliphatic)alkyl,or haloalkyl.

As used herein, an “alkenyl” group refers to an aliphatic carbon groupthat contains 2-8 (e.g., 2-6 or 2-4) carbon atoms and at least onedouble bond. Like an alkyl group, an alkenyl group can be straight orbranched. Examples of an alkenyl group include, but are not limited to,allyl, isoprenyl, 2-butenyl, and 2-hexenyl. An alkenyl group can beoptionally substituted with one or more substituents selected from GroupJ such as halo, cycloaliphatic (e.g., cycloalkyl or cycloalkenyl),heterocycloaliphatic (e.g., heterocycloalkyl or heterocycloalkenyl),aryl, heteroaryl, alkoxy, aroyl, heteroaroyl, acyl (e.g.,(aliphatic)carbonyl, (cycloaliphatic)carbonyl, or(heterocycloaliphatic)carbonyl), nitro, cyano, amido (e.g.,(cycloalkylalkyl)carbonylamino, arylcarbonylamino, aralkylcarbonylamino,(heterocycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, heteroaralkylcarbonylamino alkylaminocarbonyl,cycloalkylaminocarbonyl, heterocycloalkylaminocarbonyl,arylaminocarbonyl, or heteroarylaminocarbonyl), amino (e.g.,aliphaticamino, cycloaliphaticamino, heterocycloaliphaticamino, oraliphaticsulfonylamino), sulfonyl (e.g., alkyl-SO₂—,cycloaliphatic-SO₂—, or aryl-SO₂—), sulfinyl, sulfanyl, sulfoxy, urea,thiourea, sulfamoyl, sulfamide, oxo, carboxy, carbamoyl,cycloaliphaticoxy, heterocycloaliphaticoxy, aryloxy, heteroaryloxy,aralkyloxy, heteroaralkoxy, alkoxycarbonyl, alkylcarbonyloxy, orhydroxy. Without limitation, some examples of substituted alkenylsinclude cyanoalkenyl, alkoxyalkenyl, acylalkenyl, hydroxyalkenyl,aralkenyl, (alkoxyaryl)alkenyl, (sulfonylamino)alkenyl (such as(alkyl-SO₂-amino)alkenyl), aminoalkenyl, amidoalkenyl,(cycloaliphatic)alkenyl, or haloalkenyl.

As used herein, an “alkynyl” group refers to an aliphatic carbon groupthat contains 2-8 (e.g., 2-6 or 2-4) carbon atoms and has at least onetriple bond. An alkynyl group can be straight or branched. Examples ofan alkynyl group include, but are not limited to, propargyl and butynyl.An alkynyl group can be optionally substituted with one or moresubstituents selected from Group J such as aroyl, heteroaroyl, alkoxy,cycloalkyloxy, heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyloxy,nitro, carboxy, cyano, halo, hydroxy, sulfo, mercapto, sulfanyl (e.g.,aliphaticsulfanyl or cycloaliphaticsulfanyl), sulfinyl (e.g.,aliphaticsulfinyl or cycloaliphaticsulfinyl), sulfonyl (e.g.,aliphatic-SO₂—, aliphaticamino-SO₂—, or cycloaliphatic-SO₂—), amido(e.g., aminocarbonyl, alkylaminocarbonyl, alkylcarbonylamino,cycloalkylaminocarbonyl, heterocycloalkylaminocarbonyl,cycloalkylcarbonylamino, arylaminocarbonyl, arylcarbonylamino,aralkylcarbonylamino, (heterocycloalkyl)carbonylamino,(cycloalkylalkyl)carbonylamino, heteroaralkylcarbonylamino,heteroarylcarbonylamino or heteroarylaminocarbonyl), urea, thiourea,sulfamoyl, sulfamide, alkoxycarbonyl, alkylcarbonyloxy, cycloaliphatic,heterocycloaliphatic, aryl, heteroaryl, acyl (e.g.,(cycloaliphatic)carbonyl or (heterocycloaliphatic)carbonyl), amino(e.g., aliphaticamino), sulfoxy, oxo, carboxy, carbamoyl,(cycloaliphatic)oxy, (heterocycloaliphatic)oxy, or (heteroaryl)alkoxy.

As used herein, an “amido” encompasses both “aminocarbonyl” and“carbonylamino.” These terms, when used alone or in connection withanother group, refer to an amido group such as —N(R^(X))—C(O)—R^(Y) or—C(O)—N(R^(X))₂, when used terminally; and they refer to an amide groupsuch as —C(O)—N(R^(X))— or —N(R^(X))—C(O)— when used internally, whereinR^(X) and R^(Y) are defined below. Examples of amido groups includealkylamido (such as alkylcarbonylamino or alkylaminocarbonyl),(heterocycloaliphatic)amido, (heteroaralkyl)amido, (heteroaryl)amido,(heterocycloalkyl)alkylamido, arylamido, aralkylamido,(cycloalkyl)alkylamido, or cycloalkylamido.

As used herein, an “amino” group refers to —NR^(X)R^(Y), wherein each ofR^(X) and R^(Y) is independently hydrogen, aliphatic, cycloaliphatic,(cycloaliphatic)aliphatic, aryl, araliphatic, heterocycloaliphatic,(heterocycloaliphatic)aliphatic, heteroaryl, carboxy, sulfanyl,sulfinyl, sulfonyl, (aliphatic)carbonyl, (cycloaliphatic)carbonyl,((cycloaliphatic)aliphatic)carbonyl, arylcarbonyl,(araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, (heteroaryl)carbonyl, or(heteroaraliphatic)carbonyl, each of which being defined herein andbeing optionally substituted. Examples of amino groups includealkylamino, dialkylamino, or arylamino. When the term “amino” is not theterminal group (e.g., alkylcarbonylamino), it is represented by—NR^(X)—. R^(X) has the same meaning as defined above.

As used herein, an “aryl” group used alone or as part of a larger moietyas in “aralkyl”, “aralkoxy”, or “aryloxyalkyl” refers to monocyclic(e.g., phenyl); bicyclic (e.g., indenyl, naphthalenyl,tetrahydronaphthyl, tetrahydroindenyl); and tricyclic (e.g., fluorenyltetrahydrofluorenyl, or tetrahydroanthracenyl, anthracenyl) ring systemsin which the monocyclic ring system is aromatic or at least one of therings in a bicyclic or tricyclic ring system is aromatic. The bicyclicand tricyclic groups include benzofused 2- to 3-membered carbocyclicrings. For example, a benzofused group includes phenyl fused with two ormore C₄₋₈ carbocyclic moieties. An aryl is optionally substituted withone or more substituents such as aliphatic (e.g., alkyl, alkenyl, oralkynyl); cycloaliphatic; (cycloaliphatic)aliphatic;heterocycloaliphatic; (heterocycloaliphatic)aliphatic; aryl; heteroaryl;alkoxy; (cycloaliphatic)oxy; (heterocycloaliphatic)oxy; aryloxy;heteroaryloxy; (araliphatic)oxy; (heteroaraliphatic)oxy; aroyl;heteroaroyl; amino; oxo (on a non-aromatic carbocyclic ring of abenzofused bicyclic or tricyclic aryl); nitro; carboxy; amido; acyl(e.g., aliphaticcarbonyl; (cycloaliphatic)carbonyl;((cycloaliphatic)aliphatic)carbonyl; (araliphatic)carbonyl;(heterocycloaliphatic)carbonyl;((heterocycloaliphatic)aliphatic)carbonyl; or(heteroaraliphatic)carbonyl); sulfonyl (e.g., aliphatic-SO₂— oramino-SO₂—); sulfinyl (e.g., aliphatic-S(O)— or cycloaliphatic-S(O)—);sulfanyl (e.g., aliphatic-S—); cyano; halo; hydroxy; mercapto; sulfoxy;urea; thiourea; sulfamoyl; sulfamide; or carbamoyl. Alternatively, anaryl can be unsubstituted.

Non-limiting examples of substituted aryls include haloaryl (e.g.,mono-, di- (such as p,m-dihaloaryl), or (trihalo)aryl); (carboxy)aryl(e.g., (alkoxycarbonyl)aryl, ((aralkyl)carbonyloxy)aryl, or(alkoxycarbonyl)aryl); (amido)aryl (e.g., (aminocarbonyl)aryl,(((alkylamino)alkyl)aminocarbonyl)aryl, (alkylcarbonyl)aminoaryl,(arylaminocarbonyl)aryl, or (((heteroaryl)amino)carbonyl)aryl);aminoaryl (e.g., ((alkylsulfonyl)amino)aryl or ((dialkyl)amino)aryl);(cyanoalkyl)aryl; (alkoxy)aryl; (sulfamoyl)aryl (e.g.,(aminosulfonyl)aryl); (alkylsulfonyl)aryl; (cyano)aryl;(hydroxyalkyl)aryl; ((alkoxy)alkyl)aryl; (hydroxy)aryl,((carboxy)alkyl)aryl; (((dialkyl)amino)alkyl)aryl; (nitroalkyl)aryl;(((alkylsulfonyl)amino)alkyl)aryl; ((heterocycloaliphatic)carbonyl)aryl;((alkylsulfonyl)alkyl)aryl; (cyanoalkyl)aryl; (hydroxyalkyl)aryl;(alkylcarbonyl)aryl; alkylaryl; (trihaloalkyl)aryl;p-amino-m-alkoxycarbonylaryl; p-amino-m-cyanoaryl; p-halo-m-aminoaryl;or (m-(heterocycloaliphatic)-o-(alkyl))aryl.

As used herein, an “araliphatic” group, such as “aralkyl,” refers to analiphatic group (e.g., a C₁₋₄ alkyl group) that is substituted with anaryl group. “Aliphatic,” “alkyl,” and “aryl” are defined herein. Anexample of araliphatic such as an aralkyl group is benzyl.

As used herein, an “aralkyl” group refers to an alkyl group (e.g., aC₁₋₄ alkyl group) that is substituted with an aryl group. Both “alkyl”and “aryl” have been defined above. An example of an aralkyl group isbenzyl. An aralkyl is optionally substituted with one or moresubstituents such as aliphatic (e.g., substituted or unsubstitutedalkyl, alkenyl, or alkynyl, including carboxyalkyl, hydroxyalkyl, orhaloalkyl such as trifluoromethyl), cycloaliphatic (e.g., substituted orunsubstituted cycloalkyl or cycloalkenyl), (cycloalkyl)alkyl,heterocycloalkyl, (heterocycloalkyl)alkyl, aryl, heteroaryl, alkoxy,cycloalkyloxy, heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyloxy,heteroaralkyloxy, aroyl, heteroaroyl, nitro, carboxy, alkoxycarbonyl,alkylcarbonyloxy, amido (e.g., aminocarbonyl, alkylcarbonylamino,cycloalkylcarbonylamino, (cycloalkylalkyl)carbonylamino,arylcarbonylamino, aralkylcarbonylamino,(heterocycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, or heteroaralkylcarbonylamino), cyano, halo,hydroxy, acyl, mercapto, alkylsulfanyl, sulfoxy, urea, thiourea,sulfamoyl, sulfamide, oxo, or carbamoyl.

As used herein, a “bicyclic ring system” includes 8- to 12- (e.g., 9,10, or 11) membered structures that form two rings, wherein the tworings have at least one atom in common (e.g., 2 atoms in common).Bicyclic ring systems include bicycloaliphatics (e.g., bicycloalkyl orbicycloalkenyl), bicycloheteroaliphatics, bicyclic aryls, and bicyclicheteroaryls.

As used herein, a “cycloaliphatic” group encompasses a “cycloalkyl”group and a “cycloalkenyl” group, each of which being optionallysubstituted as set forth below.

As used herein, a “cycloalkyl” group refers to a saturated carbocyclicmono- or bicyclic (fused or bridged) ring of 3-10 (e.g., 5-10) carbonatoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, cubyl,octahydro-indenyl, decahydro-naphthyl, bicyclo[3.2.1]octyl,bicyclo[2.2.2]octyl, bicyclo[3.3.1]nonyl, bicyclo[3.3.2.]decyl,bicyclo[2.2.2]octyl, adamantyl, azacycloalkyl, or((aminocarbonyl)cycloalkyl)cycloalkyl. A “cycloalkenyl” group, as usedherein, refers to a non-aromatic carbocyclic ring of 3-10 (e.g., 4-8)carbon atoms having one or more double bonds. Examples of cycloalkenylgroups include cyclopentenyl, 1,4-cyclohexa-di-enyl, cycloheptenyl,cyclooctenyl, hexahydro-indenyl, octahydro-naphthyl, cyclohexenyl,cyclopentenyl, bicyclo[2.2.2]octenyl, or bicyclo[3.3.1]nonenyl. Acycloalkyl or cycloalkenyl group can be optionally substituted with oneor more substituents selected from Group J such as aliphatic (e.g.,alkyl, alkenyl, or alkynyl), cycloaliphatic, (cycloaliphatic) aliphatic,heterocycloaliphatic, (heterocycloaliphatic) aliphatic, aryl,heteroaryl, alkoxy, (cycloaliphatic)oxy, (heterocycloaliphatic)oxy,aryloxy, heteroaryloxy, (araliphatic)oxy, (heteroaraliphatic)oxy, aroyl,heteroaroyl, amino, amido (e.g., (aliphatic)carbonylamino,(cycloaliphatic)carbonylamino, ((cycloaliphatic)aliphatic)carbonylamino,(aryl)carbonylamino, (araliphatic)carbonylamino,(heterocycloaliphatic)carbonylamino,((heterocycloaliphatic)aliphatic)carbonylamino,(heteroaryl)carbonylamino, or ((heteroaraliphatic)carbonylamino), nitro,carboxy (e.g., HOOC—, alkoxycarbonyl, or alkylcarbonyloxy), acyl ((e.g.,(cycloaliphatic)carbonyl, (cycloaliphatic) aliphatic)carbonyl,(araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, or(heteroaraliphatic)carbonyl), cyano, halo, hydroxy, mercapto, sulfonyl(e.g., alkyl-SO₂— and aryl-SO₂—), sulfinyl ((e.g., alkyl-S(O)—),sulfanyl (e.g., alkyl-S—), sulfoxy, urea, thiourea, sulfamoyl,sulfamide, oxo, or carbamoyl.

As used herein, “cyclic moiety” includes cycloaliphatic,heterocycloaliphatic, aryl, or heteroaryl, each of which has beendefined previously.

As used herein, the term “heterocycloaliphatic” encompasses aheterocycloalkyl group and a heterocycloalkenyl group, each of whichbeing optionally substituted as set forth below.

As used herein, a “heterocycloalkyl” group refers to a 3-10 memberedmono- or bicylic (fused or bridged) (e.g., 5- to 10-membered mono- orbicyclic) saturated ring structure, in which one or more of the ringatoms is a heteroatom (e.g., N, O, S, or combinations thereof). Examplesof a heterocycloalkyl group include piperidyl, piperazyl,tetrahydropyranyl, tetrahydrofuryl, 1,4-dioxolanyl, 1,4-dithianyl,1,3-dioxolanyl, oxazolidyl, isoxazolidyl, morpholinyl, thiomorpholyl,octahydrobenzofuryl, octahydrochromenyl, octahydrothiochromenyl,octahydroindolyl, octahydropyrindinyl, decahydroquinolinyl,octahydrobenzo[b]thiophenyl, 2-oxa-bicyclo[2.2.2]octyl,1-aza-bicyclo[2.2.2]octyl, 3-aza-bicyclo[3.2.1]octyl, and2,6-dioxa-tricyclo[3.3.1.0^(3,7)]nonyl. A monocyclic heterocycloalkylgroup can be fused with a phenyl moiety such as tetrahydroisoquinoline.A “heterocycloalkenyl” group, as used herein, refers to a mono- orbicylic (e.g., 5- to 10-membered mono- or bicyclic) non-aromatic ringstructure having one or more double bonds, and wherein one or more ofthe ring atoms is a heteroatom (e.g., N, O, or S). Monocyclic andbicycloheteroaliphatics are numbered according to standard chemicalnomenclature.

A heterocycloalkyl or heterocycloalkenyl group can be optionallysubstituted with one or more substituents selected from Group J such asaliphatic (e.g., alkyl, alkenyl, or alkynyl), cycloaliphatic,(cycloaliphatic)aliphatic, heterocycloaliphatic,(heterocycloaliphatic)aliphatic, aryl, heteroaryl, alkoxy,(cycloaliphatic)oxy, (heterocycloaliphatic)oxy, aryloxy, heteroaryloxy,(araliphatic)oxy, (heteroaraliphatic)oxy, aroyl, heteroaroyl, amino,amido (e.g., (aliphatic)carbonylamino, (cycloaliphatic)carbonylamino,((cycloaliphatic) aliphatic)carbonylamino, (aryl)carbonylamino,(araliphatic)carbonylamino, (heterocycloaliphatic)carbonylamino,((heterocycloaliphatic) aliphatic)carbonylamino,(heteroaryl)carbonylamino, or (heteroaraliphatic)carbonylamino), nitro,carboxy (e.g., HOOC—, alkoxycarbonyl, or alkylcarbonyloxy), acyl ((e.g.,(cycloaliphatic)carbonyl, ((cycloaliphatic) aliphatic)carbonyl,(araliphatic)carbonyl, (heterocycloaliphatic)carbonyl,((heterocycloaliphatic)aliphatic)carbonyl, or(heteroaraliphatic)carbonyl), nitro, cyano, halo, hydroxy, mercapto,sulfonyl (e.g., alkylsulfonyl or arylsulfonyl), sulfinyl (e.g.,alkylsulfinyl), sulfanyl (e.g., alkylsulfanyl), sulfoxy, urea, thiourea,sulfamoyl, sulfamide, oxo, or carbamoyl)).

A “heteroaryl” group, as used herein, refers to a monocyclic, bicyclic,or tricyclic ring system having 4 to 15 ring atoms wherein one or moreof the ring atoms is a heteroatom (e.g., N, O, S, or combinationsthereof) and in which the monocyclic ring system is aromatic or at leastone of the rings in the bicyclic or tricyclic ring systems is aromatic.A heteroaryl group includes a benzofused ring system having 2 to 3rings. For example, a benzofused group includes benzo fused with one ortwo 4 to 8 membered heterocycloaliphatic moieties (e.g., indolizyl,indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl,benzo[b]thiophenyl, quinolinyl, or isoquinolinyl). Some examples ofheteroaryl are azetidinyl, pyridyl, 1H-indazolyl, furyl, pyrrolyl,thienyl, thiazolyl, oxazolyl, imidazolyl, tetrazolyl, benzofuryl,isoquinolinyl, benzthiazolyl, xanthene, thioxanthene, phenothiazine,dihydroindole, benzo[1,3]dioxole, benzo[b]furyl, benzo[b]thiophenyl,indazolyl, benzimidazolyl, benzthiazolyl, puryl, cinnolyl, quinolyl,quinazolyl, cinnolyl, phthalazyl, quinazolyl, quinoxalyl, isoquinolyl,4H-quinolinyl, benzo-1,2,5-thiadiazolyl, or 1,8-naphthyridyl.

Without limitation, monocyclic heteroaryls include furyl, thiophenyl,2H-pyrrolyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl,isoxazolyl, isothiazolyl, 1,3,4-thiadiazolyl, 2H-pyranyl, 4-H-pyranyl,pyridyl, pyridazyl, pyrimidyl, pyrazolyl, pyrazyl, or 1,3,5-triazyl.Monocyclic heteroaryls are numbered according to standard chemicalnomenclature.

Without limitation, bicyclic heteroaryls include indolizyl, indolyl,isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl, benzo[b]thiophenyl,quinolinyl, isoquinolinyl, indolizyl, isoindolyl, indolyl,benzo[b]furyl, bexo[b]thiophenyl, indazolyl, benzimidazyl,benzthiazolyl, purinyl, 4H-quinolinyl, quinolyl, isoquinolyl, cinnolyl,phthalazyl, quinazolyl, quinoxalyl, 1,8-naphthyridyl, or pteridyl.Bicyclic heteroaryls are numbered according to standard chemicalnomenclature.

A heteroaryl is optionally substituted with one or more substituentssuch as aliphatic (e.g., alkyl, alkenyl, or alkynyl); cycloaliphatic;(cycloaliphatic)aliphatic; heterocycloaliphatic;(heterocycloaliphatic)aliphatic; aryl; heteroaryl; alkoxy;(cycloaliphatic)oxy; (heterocycloaliphatic)oxy; aryloxy; heteroaryloxy;(araliphatic)oxy; (heteroaraliphatic)oxy; aroyl; heteroaroyl; amino; oxo(on a non-aromatic carbocyclic or heterocyclic ring of a bicyclic ortricyclic heteroaryl); carboxy; amido; acyl (e.g., aliphaticcarbonyl;(cycloaliphatic)carbonyl; ((cycloaliphatic)aliphatic)carbonyl;(araliphatic)carbonyl; (heterocycloaliphatic)carbonyl;((heterocycloaliphatic)aliphatic)carbonyl; or(heteroaraliphatic)carbonyl); sulfonyl (e.g., aliphaticsulfonyl oraminosulfonyl); sulfinyl (e.g., aliphaticsulfinyl); sulfanyl (e.g.,aliphaticsulfanyl); nitro; cyano; halo; hydroxy; mercapto; sulfoxy;urea; thiourea; sulfamoyl; sulfamide; or carbamoyl. Alternatively, aheteroaryl can be unsubstituted.

Non-limiting examples of substituted heteroaryls include(halo)heteroaryl (e.g., mono- and di-(halo)heteroaryl);(carboxy)heteroaryl (e.g., (alkoxycarbonyl)heteroaryl); cyanoheteroaryl;aminoheteroaryl (e.g., ((alkylsulfonyl)amino)heteroaryl and((dialkyl)amino)heteroaryl); (amido)heteroaryl (e.g.,aminocarbonylheteroaryl, ((alkylcarbonyl)amino)heteroaryl,((((alkyl)amino)alkyl)aminocarbonyl)heteroaryl,(((heteroaryl)amino)carbonyl)heteroaryl,((heterocycloaliphatic)carbonyl)heteroaryl, or((alkylcarbonyl)amino)heteroaryl); (cyanoalkyl)heteroaryl;(alkoxy)heteroaryl; (sulfamoyl)heteroaryl (e.g.,(aminosulfonyl)heteroaryl); (sulfonyl)heteroaryl ((e.g.,(alkylsulfonyl)heteroaryl); (hydroxyalkyl)heteroaryl;(alkoxyalkyl)heteroaryl; (hydroxy)heteroaryl;((carboxy)alkyl)heteroaryl; (((dialkyl)amino)alkyl)heteroaryl;(heterocycloaliphatic)heteroaryl; (cycloaliphatic)heteroaryl;(nitroalkyl)heteroaryl; (((alkylsulfonyl)amino)alkyl)heteroaryl;((alkylsulfonyl)alkyl)heteroaryl; (cyanoalkyl)heteroaryl;(acyl)heteroaryl (e.g., (alkylcarbonyl)heteroaryl); (alkyl)heteroaryl;and (haloalkyl)heteroaryl (e.g., trihaloalkylheteroaryl).

A “heteroaraliphatic” (such as a heteroaralkyl group) as used herein,refers to an aliphatic group (e.g., a C₁₋₄ alkyl group) that issubstituted with a heteroaryl group. “Aliphatic,” “alkyl,” and“heteroaryl” have been defined above.

A “heteroaralkyl” group, as used herein, refers to an alkyl group (e.g.,a C₁₋₄ alkyl group) that is substituted with a heteroaryl group. Both“alkyl” and “heteroaryl” have been defined above. A heteroaralkyl isoptionally substituted with one or more substituents such as alkyl(including carboxyalkyl, hydroxyalkyl, and haloalkyl such astrifluoromethyl), alkenyl, alkynyl, cycloalkyl, (cycloalkyl)alkyl,heterocycloalkyl, (heterocycloalkyl)alkyl, aryl, heteroaryl, alkoxy,cycloalkyloxy, heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyloxy,heteroaralkyloxy, aroyl, heteroaroyl, nitro, carboxy, alkoxycarbonyl,alkylcarbonyloxy, aminocarbonyl, alkylcarbonylamino,cycloalkylcarbonylamino, (cycloalkylalkyl)carbonylamino,arylcarbonylamino, aralkylcarbonylamino,(heterocycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, heteroaralkylcarbonylamino, cyano, halo,hydroxy, acyl, mercapto, alkylsulfanyl, sulfoxy, urea, thiourea,sulfamoyl, sulfamide, oxo, or carbamoyl.

As used herein, an “acyl” group refers to a formyl group or R^(X)—C(O)—(such as alkyl-C(O)—, also referred to as “alkylcarbonyl”) wherein R^(X)and “alkyl” have been defined previously. Acetyl and pivaloyl areexamples of acyl groups.

As used herein, an “aroyl” or “heteroaroyl” refers to an aryl-C(O)— or aheteroaryl-C(O)—. The aryl and heteroaryl portion of the aroyl orheteroaroyl is optionally substituted as previously defined.

As used herein, an “alkoxy” group refers to an alkyl-O— group wherein“alkyl” has been defined previously.

As used herein, a “carbamoyl” group refers to a group having thestructure —O—CO—NR^(X)R^(Y) or —NR^(X)—CO—O—R^(Z) wherein R^(X) andR^(Y) have been defined above and R^(Z) can be aliphatic, aryl,araliphatic, heterocycloaliphatic, heteroaryl, or heteroaraliphatic.

As used herein, a “carboxy” group refers to —COOH, —COOR^(X), —OC(O)H,—OC(O)R^(X) when used as a terminal group; or —OC(O)— or —C(O)O— whenused as an internal group.

As used herein, a “haloaliphatic” group refers to an aliphatic groupsubstituted with 1-3 halogen. For instance, the term haloalkyl includesthe group —CF₃.

As used herein, a “mercapto” group refers to —SH.

As used herein, a “sulfo” group refers to —SO₃H or —SO₃R^(X) when usedterminally or —S(O)₃— when used internally.

As used herein, a “sulfamide” group refers to the structure—NR^(X)—S(O)₂—NR^(Y)R^(Z) when used terminally and —NR^(X)—S(O)₂—NR^(Y)—when used internally, wherein R^(X), R^(Y), and R^(Z) have been definedabove.

As used herein, a “sulfonamide” group refers to the structure—S(O)₂—NR^(X)R^(Y) or —NR^(X)—S(O)²—R^(Z) when used terminally; or—S(O)₂—NR^(X)— or —NR^(X)—S(O)₂— when used internally, wherein R^(X),R^(Y), and R^(Z) are defined above.

As used herein a “sulfanyl” group refers to —S—R^(X) when usedterminally and —S— when used internally, wherein R^(X) has been definedabove. Examples of sulfanyl include aliphatic-S—, cycloaliphatic-S—,aryl-S—, or the like.

As used herein a “sulfinyl” group refers to —S(O)—R^(X) when usedterminally and —S(O)— when used internally, wherein R^(X) has beendefined above. Exemplary sulfinyl groups include aliphatic-S(O)—,aryl-S(O)—, (cycloaliphatic(aliphatic))-S(O)—, cycloalkyl-S(O)—,heterocycloaliphatic-S(O)—, heteroaryl-S(O)—, or the like.

As used herein, a “sulfonyl” group refers to —S(O)₂—R^(X) when usedterminally and —S(O)₂— when used internally, wherein R^(X) has beendefined above. Exemplary sulfonyl groups include aliphatic-S(O)₂—,aryl-S(O)₂—, ((cycloaliphatic(aliphatic))-S(O)₂—, cycloaliphatic-S(O)₂—,heterocycloaliphatic-S(O)₂—, heteroaryl-S(O)₂—,(cycloaliphatic(amido(aliphatic)))-S(O)₂— or the like.

As used herein, a “sulfoxy” group refers to —O—SO—R^(X) or —SO—O—R^(X),when used terminally and —O—S(O)— or —S(O)—O— when used internally,wherein R^(X) has been defined above.

As used herein, a “halogen” or “halo” group refers to fluorine,chlorine, bromine, or iodine.

As used herein, an “alkoxycarbonyl” group, which is encompassed by“carboxy,” used alone or in combination with another group, refers to agroup such as alkyl-O—C(O)—.

As used herein, an “alkoxyalkyl” group refers to an alkyl group such asalkyl-O-alkyl-, wherein alkyl has been defined above.

As used herein, a “carbonyl” group refer to —C(O)—.

As used herein, an “oxo” group refers to ═O.

As used herein, an “aminoalkyl” group refers to the structure(R^(X))₂N-alkyl-.

As used herein, a “cyanoalkyl” group refers to the structure(NC)-alkyl-.

As used herein, a “urea” group refers to the structure—NR^(X)—CO—NR^(Y)R^(Z) and a “thiourea” group refers to the structure—NR^(X)—CS—NR^(Y)R^(Z) when used terminally and —NR^(X)—CO—NR^(Y)— or

—NR^(X)—CS—NR^(Y)— when used internally, wherein R^(X), R^(Y), and R^(Z)have been defined above.

As used herein, a “guanidine” group refers to the structure—N═C(N(R^(X)R^(Y)))N(R^(X)R^(Y)) or

—NR^(X)—C(═NR^(X))NR^(X)R^(Y), wherein R^(X) and R^(Y) have been definedabove.

As used herein, an “amidino” group refers to the structure—C═(NR^(X))N(R^(X)R^(Y)), wherein R^(X) and R^(Y) have been definedabove.

In general, the term “vicinal” refers to the placement of substituentson a group that includes two or more carbon atoms, wherein thesubstituents are attached to adjacent carbon atoms.

In general, the term “geminal” refers to the placement of substituentson a group that includes two or more carbon atoms, wherein thesubstituents are attached to the same carbon atom.

The terms “terminally” and “internally” refer to the location of a groupwithin a substituent. A group is terminal when the group is present atthe end of the substituent not further bonded to the rest of thechemical structure. Carboxyalkyl, i.e., R^(X)O(O)C-alkyl is an exampleof a carboxy group used terminally. A group is internal when the groupis present in the middle of a substituent to at the end of thesubstituent bound to the rest of the chemical structure. Alkylcarboxy(e.g., alkyl-C(O)—O— or alkyl-O—C(O)—) and alkylcarboxyaryl (e.g.,alkyl-C(O)—O-aryl- or alkyl-O—C(O)-aryl-) are examples of carboxy groupsused internally.

As used herein, a “cyclic” group includes a mono-, bi-, and tri-cyclicring system, such as cycloaliphatic, heterocycloaliphatic, aryl, orheteroaryl, each of which has been defined above.

As used herein, a “bridged bicyclic ring system” refers to a bicyclicheterocyclicaliphatic ring system or bicyclic cycloaliphatic ring systemin which the rings are bridged. Examples of bridged bicyclic ringsystems include, but are not limited to, adamantanyl, norbornanyl,bicyclo[3.2.1]octyl, bicyclo[2.2.2]octyl, bicyclo[3.3.1]nonyl,bicyclo[3.2.3]nonyl, 2-oxabicyclo[2.2.2]octyl, 1-azabicyclo[2.2.2]octyl,3-azabicyclo[3.2.1]octyl, and 2,6-dioxa-tricyclo[3.3.1.0^(3,7)]nonyl. Abridged bicyclic ring system can be optionally substituted with one ormore substituents such as alkyl (including carboxyalkyl, hydroxyalkyl,and haloalkyl such as trifluoromethyl), alkenyl, alkynyl, cycloalkyl,(cycloalkyl)alkyl, heterocycloalkyl, (heterocycloalkyl)alkyl, aryl,heteroaryl, alkoxy, cycloalkyloxy, heterocycloalkyloxy, aryloxy,heteroaryloxy, aralkyloxy, heteroaralkyloxy, aroyl, heteroaroyl, nitro,carboxy, alkoxycarbonyl, alkylcarbonyloxy, aminocarbonyl,alkylcarbonylamino, cycloalkylcarbonylamino,(cycloalkylalkyl)carbonylamino, arylcarbonylamino, aralkylcarbonylamino,(heterocycloalkyl)carbonylamino, (heterocycloalkylalkyl)carbonylamino,heteroarylcarbonylamino, heteroaralkylcarbonylamino, cyano, halo,hydroxy, acyl, mercapto, alkylsulfanyl, sulfoxy, urea, thiourea,sulfamoyl, sulfamide, oxo, or carbamoyl.

As used herein, an “aliphatic chain” refers to a branched or straightaliphatic group (e.g., alkyl groups, alkenyl groups, or alkynyl groups).A straight aliphatic chain has the structure —(CH₂)_(v)—, where v is1-6. A branched aliphatic chain is a straight aliphatic chain that issubstituted with one or more aliphatic groups. A branched aliphaticchain has the structure —(CHQ)_(v)- where Q is hydrogen or an aliphaticgroup; however, Q shall be an aliphatic group in at least one instance.The term aliphatic chain includes alkyl chains, alkenyl chains, andalkynyl chains, where alkyl, alkenyl, and alkynyl are defined above.

The phrase “optionally substituted” is used interchangeably with thephrase “substituted or unsubstituted.” As described herein, compounds ofthe invention can optionally be substituted with one or moresubstituents, such as are illustrated generally above, or as exemplifiedby particular classes, subclasses, and species of the invention. Asdescribed herein, the variables R₁, R₂, and R₃, as well as othervariables, encompass specific groups, such as alkyl and aryl. Unlessotherwise noted, each of the specific groups for the variables R₁, R₂,and R₃, and other variables contained therein can be optionallysubstituted with one or more substituents described herein. Eachsubstituent of a specific group is further optionally substituted withone to three of halo, cyano, oxo, alkoxy, hydroxy, amino, nitro, aryl,cycloaliphatic, heterocycloaliphatic, heteroaryl, haloalkyl, and alkyl.For instance, an alkyl group can be substituted with alkylsulfanyl andthe alkylsulfanyl can be optionally substituted with one to three ofhalo, cyano, oxo, alkoxy, hydroxy, amino, nitro, aryl, haloalkyl, andalkyl. As an additional example, the cycloalkyl portion of a(cycloalkyl)carbonylamino can be optionally substituted with one tothree of halo, cyano, alkoxy, hydroxy, nitro, haloalkyl, and alkyl. Whentwo alkoxy groups are bound to the same atom or adjacent atoms, the twoalkoxy groups can form a ring together with the atom(s) to which theyare bound.

In general, the term “substituted,” whether preceded by the term“optionally” or not, refers to the replacement of hydrogen radicals in agiven structure with the radical of a specified substituent. Specificsubstituents are described above in the definitions and below in thedescription of compounds and examples thereof. Unless otherwiseindicated, an optionally substituted group can have a substituent ateach substitutable position of the group, and when more than oneposition in any given structure can be substituted with more than onesubstituent selected from a specified group, the substituent can beeither the same or different at every position. A ring substituent, suchas a heterocycloalkyl, can be bound to another ring, such as acycloalkyl, to form a spiro-bicyclic ring system, e.g., both rings shareone common atom. Combinations of substituents envisioned by thisinvention are those combinations that result in the formation of stableor chemically feasible compounds.

The phrase “stable or chemically feasible,” as used herein, refers tocompounds that are not substantially altered when subjected toconditions to allow for their production, detection, and preferablytheir recovery, purification, and use for one or more of the purposesdisclosed herein. In some embodiments, a stable compound or chemicallyfeasible compound is one that is not substantially altered when kept ata temperature of 40° C. or less, in the absence of moisture or otherchemically reactive conditions, for at least a week.

As used herein, an effective amount is defined as the amount required toconfer a therapeutic effect on the treated patient, and is typicallydetermined based on age, surface area, weight, and condition of thepatient. The interrelationship of dosages for animals and humans (basedon milligrams per meter squared of body surface) is described byFreireich et al., Cancer Chemother. Rep., 50: 219 (1966). Body surfacearea may be approximately determined from height and weight of thepatient. See, e.g., Scientific Tables, Geigy Pharmaceuticals, Ardsley,N.Y., 537 (1970). As used herein, “patient” refers to a mammal,including a human.

Unless otherwise stated, structures depicted herein are also meant toinclude all isomeric (e.g., enantiomeric, diastereomeric, and geometric(or conformational)) forms of the structure; for example, the R and Sconfigurations for each asymmetric center, (Z) and (E) double bondisomers, and (Z) and (E) conformational isomers. Therefore, singlestereochemical isomers as well as enantiomeric, diastereomeric, andgeometric (or conformational) mixtures of the present compounds arewithin the scope of the invention. Unless otherwise stated, alltautomeric forms of the compounds of the invention are within the scopeof the invention. Additionally, unless otherwise stated, structuresdepicted herein are also meant to include compounds that differ only inthe presence of one or more isotopically enriched atoms. For example,compounds having the present structures except for the replacement ofhydrogen by deuterium or tritium, or the replacement of a carbon by a¹³C- or ¹⁴C-enriched carbon are within the scope of this invention. Suchcompounds are useful, for example, as analytical tools or probes inbiological assays.

As used herein, EDC is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide,HOBt is 1-hydroxybenzotriazole, HOSuc is N-hydroxysuccinimide, THF istetrahydrofuran, TFA is trifluoroacetic acid, DCM is dichloromethane,DMAP is 4-dimethylaminopyridine, DIPEA is diisopropylethylamine, DMF isdimethylformamide, TFA is trifluoroacetic acid, and CBZ isbenzyloxycarbonyl, and TEMPO is 2,2,6,6-tetramethylpiperidinyloxy.

As used herein, ¹H NMR stands for proton nuclear magnetic resonance, andTLC stands for thin layer chromatography.

II. Processes and Intermediates

In one embodiment, the invention provides a process and intermediatesfor preparing a compound of formula 1 as outlined in Scheme I.

Referring to Scheme 1,3-azabicyclo[3.3.0]octane of formula 5 (R. Griot,Helv. Chim. Acta., 42, 67, (1959) is converted to a suitable alkylcarbamate of formula 6 wherein R′ is, e.g., t-butyl or isobutyl, usingknown methods. See, e.g., T. W. Greene and P. G. M. Wuts, ProtectiveGroups in Organic Synthesis, 3^(rd) edition, John Wiley and Sons, Inc.(1999).

Carboxylation of the N-alkoxycarbonyl-3-azabicyclo[3.3.0]octane offormula 6 is achieved by first forming a 2-anion of formula 6 in thepresence of a chelating agent (for formation of similar anions. See,e.g., Daniel. J. Pippel, et. al., J. Org. Chem., 1998, 63, 2; Donald J.Gallagher et al., J. Org. Chem., 1995, 60(22), 7092-7093; Shawn T.Kerrick et al., J. Am. Chem. Soc., 1991, 113(25), 9708-9710; Donald J.Gallagher et al., J. Org. Chem., 1995, 60(25), 8148-8154; and Peter Beaket al., J. Am. Chem. Soc., 1994, 116(8), 3231-3239. The 2-anion of thealkyl carbamate of formula 6 (not shown in Scheme I) is prepared bytreatment of compound of formula 6 with a strong lithium base (e.g.,t-butyl lithium or sec-butyl lithium) in the presence of a complexingagent (e.g., tetramethylethylenediamine, tetraethylethylenediamine,tetramethyl-1,2-cyclohexyldiamine, or3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane) in a suitable aproticsolvent. Suitable aprotic solvents include, e.g., t-butylmethyl ether,tetrahydrofuran, and dimethoxyethane. Subsequently, the 2-anion offormula 6 can be treated with carbon dioxide to give a racemic mixtureof trans-/cis-2-carboxylic acids of formula 7 wherein the trans-/cis-ratio is 30 to 70, 40 to 60, 50 to 50, 60 to 40, 80 to 20, 90 to 10, 95to 5, or greater than 98 to 2.

In some embodiments, the complexing agent may be optically active, suchas, for example, an optical isomer of sparteine. An optically activecomplexing agent can induce asymmetric carboxylation to give a producthaving an enantiomeric excess (e.e.) of from about 10% to about 95%(see, e.g., Beak et. al., J. Org. Chem., 1995, 60, 8148-8154). Thetrans-/cis- mixture is equilibrated to give a predominantly trans acidof formula 8 wherein the trans-/cis- ratio is 80 to 20, 90 to 10, 95 to5, or greater than 98 to 2, in the presence of a suitable base. Suitablebases include, e.g., lithium hexamethyldisilazide, lithiumdiisopropylamide, or lithium 2,2,6,6-tetramethylpiperidine.

In another embodiment, the use of3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane as the complexing diamineprovides the carboxylic acid of formula 8 with a trans-/cis- ratio ofisomers of 90 to 10, 95 to 5, or greater than 98 to 2 directly andobviates the equilibration step.

The racemic mixture of the compound of formula 8 may be resolved toprovide a single enantiomer of formula 9. Known methods of resolvingracemic amino acids may be used and include, but are not limited to,crystallization of an optically active amine salt, preparing a2-carboxylate ester with an optically active alcohol followed bycrystallization or chromatographic separation, and preparing anoptically active N-alkoxycarbonyl derivative followed by crystallizationor chromatography. In one embodiment, the (R) α-aminoethylbenzene or (S)1-amino-1,2,3,4-tetrahydronaphthalene salt of compound of formula 8 iscrystallized to produce the amine salt of formula 9.

The free acid of the salt of formula 9, obtained by extraction of, forexample, an aqueous sodium bisulfate solution is esterified with, forexample, di-t-butyl-dicarbonate (Boc₂O) to give the ester of formula 10.Removal of the —COOR′ protecting group under known conditions, forexample, methane sulfonic acid in an organic solvent such as, forexample, t-butylmethyl ether or tetrahydrofuran, provides the compoundsof formula 1.

In another embodiment, bicyclic pyrrolidinyl compounds of Formula 3 (asexemplified by compounds 17 shown below) may be prepared as outlined inScheme II.

Referring to Scheme II, the camphor imine of formula 12 is prepared byreaction of glycine t-butyl ester of formula 11 with (1S)-(−)camphor inthe presence of a Lewis acid such as, for example, boron trifluorideetherate. Michael addition of the amine of formula 12 to methylcyclopentenecarboxylate gives an adduct of formula 13. The single isomerof compound 13 shown is obtained by recrystallization of the crudeproduct from a mixture of isopropanol and water. Removal of the camphorimine with hydroxylamine in the presence of sodium acetate andsubsequent cyclization yields the lactam ester of formula 14.Optionally, the reaction mixture may be treated with succinic anhydrideto facilitate recovery of the desired product of formula 14 and thecamphor derivative of formula 15. The lactam of formula 14 is convertedto its benzyloxycarbonyl derivative of formula 16 by treatment with abase such as, e.g., sodium hydride, followed by benzylchloroformate.Reduction of the lactam of formula 16 with a hydride reducing agent suchas, e.g., borane-dimethylsulfide-piperidine provides the carbamate esterof formula 17. Removal of the benzyloxycarbonyl protecting group may beachieved under reducing conditions such as, e.g., hydrogen in thepresence of a palladium catalyst such as, e.g., palladium hydroxide, togive the desired bicyclic pyrrolidine ester of formula 17. Isolation ofthe ester of formula 17 is optionally achieved through formation of asalt such as, e.g., an oxalate salt of formula 1a.

The invention further provides processes for the preparation ofcompounds of Formula 2. One specific example of a compound of Formula 2,wherein R′₄ is H, R′₅ is n-propyl, and R₄ is cyclopropyl, is shown belowin formula 18.

In one aspect, compound 18 can be prepared as outlined in Scheme III.

In Scheme III, the methoxymethylamide of Cbz-norvaline of formula 20 isprepared by reaction of Cbz-norvaline of formula 19 withmethoxymethylamine in the presence of a coupling reagent such as, e.g.,EDC. Reduction of compound of formula 20 with a hydride reagent such as,e.g., lithium aluminum hydride or diisobutylaluminum hydride at atemperatures between −20° C. and 10° C. provides a norvalinal compoundof formula 21. Preparation of the corresponding cyanohydrin of formula22 is achieved by reacting compound of formula 21 with an alkali metalcyanide such as, e.g., potassium cyanide, in the presence of an alkalimetal thiosulfite such as, e.g., sodium thiosulfite. Hydrolysis ofcompound of formula 22 in the presence of HCl in a suitable solvent suchas, e.g., dioxane, and at an elevated temperatures of from about 50° C.to 110° C. leads to the corresponding 3-amino-2-hydroxyhexanoic acid(not shown) which is converted to the Cbz derivative of formula 23 byreaction with Cbz-hydroxysuccinimide. The cyclopropyl amide of formula24 is prepared from compound 23 by reaction with cyclopropylamine in thepresence of a coupling reagent such as, e.g., EDC. Removal of the Cbzgroup to give a compound of formula 18 is achieved under known reducingconditions such as, e.g., hydrogen in the presence of a palladiumcatalyst.

In another embodiment, as illustrated in Scheme IV below, acyclopropylamide of Formula 18 is prepared using the Passerini reaction(see, e.g., A. Doemling et al., Angew. Chem., 2000, 112, 3300-3344).

Referring to Scheme IV, reaction of Cbz-valinal 21 with cyclopropylisocyanide of formula 25 (available from Oakwood Products, Inc., WestColumbia, S.C. 29172, USA) in the presence of trifluroacetic acid,optionally in the presence of an asymmetric catalyst provides thecyclopropylamide of formula 24. See, e.g., Schreiber, et. al., Org.Lett., 2004, 6, 4231. The intermediate trifluoracetate (not shown) ishydrolyzed during isolation to yield compound 24 directly. Removal ofthe Cbz protecting group to give the compound of formula 18 is achievedunder reducing conditions as previously described.

In another embodiment, the hydroxy-acid compounds of formula 23 may beprepared according to methods described in U.S. Pat. Nos. 6,020,518;6,087,530 and 6,639,094, each of which is incorporated herein byreference in its entirety.

Although the processes shown in schemes III and IV above illustrate thesynthesis of a specific compound (of formula 18), the processes inschemes III and IV can be used to produce other compounds of Formula 2.

In another embodiment, as illustrated in Scheme V, this inventionfurther provides a process and intermediates for preparing a compound ofFormula 4.

Referring to Scheme V, a bicyclic aminoester of Formula 1, wherein R₃ ist-butyl, is reacted with a protected amino acid of formula 26 (wherein Zis an amine protecting group and can be removed under acidic, basic orhydrogenating conditions different from those used for removing an R₃protecting group) in the presence of a coupling reagent, to give anamide-ester of formula 27. The protecting group Z is removed from theamide-ester of formula 27 to give the amine-ester compound of formula28.

Reaction of the amino-containing compound of formula 28 with theprotected amino acid 29 in the presence of a coupling reagent gives atripeptide of formula 30.

Removing the protecting group Z in the tripeptide of formula 30 providesa free amino-tripeptide of formula 31.

Reaction of the amino-tripeptide of formula 31 withpyrazine-2-carboxylic acid, of formula 32, in the presence of a couplingreagent yields the amide-tripeptide ester of formula 33.

Hydrolysis of the ester of the amide-tripeptide ester of formula 33provides the amido-tripeptide acid of formula 34;

Reacting the amido-tripeptide acid of formula 34 with the amino-hydroxyamide of formula 18 in the presence of a coupling reagent gives thehydroxy-peptide of formula 35.

In the final step, oxidation of the hydroxy group of the compound offormula 35 provides the compound of Formula 4.

Oxidation of compound 35 may be achieved with a variety of knownoxidizing reagents, such as, for example: chromic acid in acetone;Dess-Martinperiodinane(1,1-dihydro-1,1,1-triacetoxy-1,2-benzoiodooxol-3(1H)-one);sodium hypochlorite in the presence of TEMPO and, optionally, an alkalimetal halide such as sodium bromide.

In some embodiments, the configuration of the hydroxy group of 35 is amixture of R and S isomers in the ratio of from about 90 to 10 to about10 to 90, typically in a ratio of about 60 to 40 to about 40 to 60.

In another embodiment, the hydroxy group of compound 35 has the Rconfiguration with an enantiomeric excess of about 90% ee.

In a further embodiment, the hydroxy group of compound 35 has the Sconfiguration with an enantiomeric excess of about 90% ee.

Any of the intermediates obtained as described herein, may be used withor without isolation from the reaction mixture. The desired proteaseinhibitor may be derived by attaching the appropriate RW—, P₂—,P₃-L₂-P₂, or P₄-L₃-P₃-L₂-P₂— moiety. A coupling of an amine with such amoiety may be carried out using the corresponding carboxylic acid, orreactive equivalent thereof, under standard amide bond-forming orcoupling conditions. A typical coupling reaction includes a suitablesolvent, the amine in a concentration ranging from about 0.01 to 10M,preferably about 0.1 to about 4.0M, the requisite carboxylic acid, abase and a peptide coupling reagent.

If an amine is used without isolation, the coupling may be carried outin situ in the solvent of the reaction mixture used in the preparationof the amine, or in a different solvent. To this reaction mixture, therequisite carboxylic acid may be added and the reaction maintained at atemperature in the range of about 0° C. to 100° C., preferably betweenabout 20° C. to about 40° C. The base and peptide coupling reagent arethen added to the mixture, which is maintained at a temperature in therange of about 0° C. to about 60° C., preferably between about 20° C. toabout 40° C. The base is typically a tertiary amine base, such astriethylamine, di-iso-propylethylamine, N-methylmorpholine, DBU, DBN,N-methylimidazole, preferably triethylamine or diisopropylethylamine.The amount of base used is generally up to about 20 equivalents perequivalent of the amine, preferably at least about 3 equivalents ofbase. Examples of peptide coupling reagents include DCC(dicyclohexylcarbodiimide), DIC (diisopropylcarbodiimide),di-p-toluoylcarbodiimide, BDP (1-benzotriazolediethylphosphate-1-cyclohexyl-3-(2-morpholinylethyl)carbodiimide), EDC(1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride), cyanuricfluoride, cyanuric chloride, TFFH (tetramethyl fluoroformamidiniumhexafluorophosphosphate), DPPA (diphenylphosphorazidate), BOP(benzotriazol-1-yloxytris(dimethylamino)phosphoniumhexafluorophosphate), HBTU(O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate),TBTU (O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluroniumtetrafluoroborate), TSTU(O—(N-succinimidyl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate),HATU(N-[(dimethylamino)-1-H-1,2,3-triazolo[4,5,6]-pyridin-1-ylmethylene]-N-methylmethanaminiumhexafluorophosphate N-oxide), BOP—Cl(bis(2-oxo-3-oxazolidinyl)phosphinic chloride), PyBOP((1-H-1,2,3-benzotriazol-1-yloxy)-tris(pyrrolidino)phosphoniumtetrafluorophopsphate), BrOP (bromotris(dimethylamino)phosphoniumhexafluorophosphate), DEPBT(3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one), or PyBrOP(bromotris(pyrrolidino)phosphonium hexafluorophosphate). EDC, HOAT,BOP—Cl and PyBrOP are preferred peptide coupling reagents. The amount ofpeptide coupling reagent is in the range of about 1.0 to about 10.0equivalents. Optional reagents that may be used in the amidebond-forming reaction include DMAP (4-dimethylaminopyridine) or activeester reagents, such as HOBT (1-hydroxybenzotriazole), HOAT(hydroxyazabenzotriazole), HOSu (hydroxysuccinimide), HONB(endo-N-hydroxy-5-norbornene-2,3-dicarboxamide), in amounts ranging fromabout 1.0 to about 10.0 equivalents.

Alternatively, one may treat an amine with a reactive equivalent of theR₁ carboxylic acid, such as RW—C(═O)X¹, P₂—C(═O)X¹, P₃-L₂-P₂—C(═O)X¹, orP₄-L₃-P₃-L₂-P₂—C(═O)X¹, wherein C(═O)X¹ is a group that is more reactivethan COOH in the coupling reaction. Examples of —C(═O)X¹ groups includegroups where X¹ is Cl, F, OC(═O)R(R is, e.g., aliphatic or aryl), —SH,—SR, —SAr, or —SeAr.

Acid and amine protecting groups as used herein are known in the art(see, e.g., T. W. Greene & P. G. M Wutz, “Protective Groups in OrganicSynthesis,” 3^(rd) Edition, John Wiley & Sons, Inc. (1999), and theearlier editions of this book. Examples of suitable protecting groupsfor acids include t-butoxy, benzyloxy, allyloxy and methoxymethoxy.Examples of suitable protecting groups for amines include9-fluorenylmethyl carbamate, t-butyl carbamate, benzyl carbamate,trifluoroacetamide and p-toluenesulfonamide. A number of chemical groupsare known that may be used as the RW—, P₂—, P₃-L₂-P₂, orP₄-L₃-P₃-L₂-P₂-portion of the protease inhibitor. Examples of suchgroups are reported in the following publications: WO 97/43310, US20020016294, WO 01/81325, WO 02/08198, WO 01/77113, WO 02/08187, WO02/08256, WO 02/08244, WO 03/006490, WO 01/74768, WO 99/50230, WO98/17679, WO 02/48157, US 20020177725, WO 02/060926, US 20030008828, WO02/48116, WO 01/64678, WO 01/07407, WO 98/46630, WO 00/59929, WO99/07733, WO 00/09588, US 20020016442, WO 00/09543, WO 99/07734, U.S.Pat. No. 6,018,020, U.S. Pat. No. 6,265,380, U.S. Pat. No. 6,608,027, US20020032175, US 20050080017, WO 98/22496, U.S. Pat. No. 5,866,684, WO02/079234, WO 00/31129, WO 99/38888, WO 99/64442, WO 2004072243, and WO02/18369, which are incorporated herein by reference in theirentireties.

Although in Scheme V only a single stereoisomer is illustrated for thecompound of Formula 4, the present invention is, however, intended toinclude all stereoisomers of Formula 4 which are depicted in Table I.All these stereoisomers can be prepared in the same method by usingreagent(s) containing carbon atom(s) of a different stericconfiguration, e.g.,

TABLE I

III. EXAMPLES

The following preparative examples are set forth in order that thisinvention be more fully understood. These examples are for the purposeof illustration only and are not to be construed as limiting the scopeof the invention in any way.

Preparation 1: 3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane

Method 1

To a three-neck 5 L flask equipped with a mechanical stirrer,thermocouple, condenser, and addition funnel, under a nitrogenatmosphere, was charged 1-propyl-4-piperidone (100 g, 0.71 mol),paraformaldehyde (50 g, 1.67 mol), and ethyl alcohol (2.0 L) withstirring. Acetic acid (90 mL, 1.56 mol) was charged and the mixture waswarmed to 40° C. In a separate flask was dissolved propylamine (64 mL,0.78 mol) in ethyl alcohol (500 mL). This solution was added to theabove mixture over 7-8 hours. The mixture was stirred for an additional1.5 hours at 40° C., then cooled to ambient temperature. The mixture wasfiltered through a pad of Celite®, and the Celite® was rinsed with ethylalcohol (twice, 100 mL each). The solution was concentrated in vacuo anddiethyleneglycol (1.0 L) was added. In a separate flask potassiumhydroxide (160 g) was dissolved in water (190 mL). The solution wasadded to the diethyleneglycol mixture, with stirring, then the mixturewas warmed to 85° C. Hydrazine monohydrate (96 mL) was added over 2hours, and the resultant mixture was stirred at 85° C. for another 1hour. With nitrogen sparging, the mixture was warmed to 160° C. bathtemperature while collecting the distillate in a Dean-Stark trap. Thelower aqueous phase was returned to the reaction flask while the upperproduct phase collected. The process was repeated until the product nolonger distilled as an azeotrope with water. The pot temperature variedfrom 135 to 160° C. during the process. The collected upper-phasefractions were combined and dissolved in heptane (160 mL). The solutionwas washed with water (twice, 120 mL each), and the combined aqueousphases were extracted with heptane (twice, 100 mL each). The combinedorganic phases were concentrated to give the title compound (85.3 g, 57%yield).

¹H NMR (DMSO-d₆, 500 MHz): δ 2.60 (dd, J=10.88, 2.04 Hz, 4H), 2.23 (dd,J=10.88, 4.58 Hz, 4H), 2.12 (t, J=7.74 Hz, 4H), 1.91-1.84 (m, 2H),1.44-1.35 (m, 6H), 0.85 (t, J=7.25 Hz, 6H)

Method 2

Under nitrogen atmosphere, acetic acid (260 mL, 4.67 mol) was added to amixture of 1-propyl-4-piperidone (300 g, 2.12 mol), paraformaldehyde(150 g, 5.00 mol), and ethyl alcohol (6.00 L) in a four-neck 12 L flaskequipped with a mechanical stirrer, a thermocouple, and a condenser. Theheterogeneous mixture was warmed to 40° C. and a solution of propylamine(192 mL, 2.34 mol) in ethyl alcohol (1.50 L) was added over a period of7.5 hours. The mixture was maintained at 40° C. for 1.5 hours after theaddition was finished. The mixture was cooled to 22 to 25° C. andfiltered. The collected solids were washed with ethyl alcohol (twice,200 mL each) and the combined filtrates concentrated to about 1.0 Lunder vacuum distillation (90 mmHg, 50 to 55° C.). Diethyleneglycol(2.60 L) was added, followed by a solution of potassium hydroxide (477g) in water (570 mL). The reaction mixture was heated to 85° C. andhydrazine monohydrate (279 mL) was added over 2 hours. Heating at 85° C.was continued for 1 hour after the addition was finished then themixture was heated to 155° C. while collecting the distillate whichformed two layers. The lower layer was returned periodically to thereaction mixture. Heating at 155-165° C. was continued until thedistillation of the upper layer ceased. The upper product layer wasdiluted with heptane (480 mL) and washed with water (twice, 240 mL each)The combined aqueous phases were extracted with heptane (twice, 300 mLeach). The combined heptane extracts were concentrated to provide thetitle compound (233 g, 52% yield) as a straw colored liquid.

Preparation 2: (S)-3-amino-N-cyclopropyl-2-hydroxyhexanamide (18)

A 250 mL round bottomed flask equipped with an overhead stirrer,addition funnel, thermocouple, and nitrogen/hydrogen inlet was purgedwith nitrogen for several minutes. The protected amino-hydroxy acid(10.0 g, 0.035 mol) and N-hydroxysuccinimide (9.0 g, 0.078 mol, 2.2molar eq.) were added to the flask followed by 105 mL of DMF. Themixture was agitated at 20±5° C. until a clear solution was obtained(approximately 15 minutes). The flask was cooled to −9.8° C.(ice/acetone bath). EDC-HCl (13.6 g, 0.071 mol, 2.0 molar eq.) was addedto the flask in one portion. The contents of the flask were allowed tostir at −5±5° C. for 3 hours. The contents of the reaction flask werecooled to −10±3° C. and cyclopropyl amine (4.89 g, 0.085 mol, 2.4 molareq.) was added via an addition funnel while maintaining a temperaturerange of 5±3° C. The reaction mixture was allowed to stir at 5±5° C. for60 minutes then slowly warmed to room temperature and stirred overnight.The reaction mixture was transferred to a larger round bottom flask andquenched with the addition of water (270 mL) at room temperature. TheDMF/water layer was extracted with three portions of EtOAc (150 mL) at35-40° C., the combined EtOAc extracts were washed with water (twice,300 mL each), followed by 10% NaHCO₃ solution (300 mL), and finallywater (300 mL). The EtOAc layer was concentrated at atmospheric pressureand heptane (100 mL) was added. Distillation at 80±5° C. was continuedand additional heptane (50 mL) was added to crystallize the product fromsolution. The mixture was held at 85° C. for 2 hours, slowly cooled toroom temperature, and held for 1 hour. The product was vacuum filteredand dried at 25 mmHg overnight at 30° C. to give a crude product (12.86g). An 11.44 g portion of the crude product was placed in a 250 mL roundbottom flask, 50 mL of MTBE was added, and the thick slurry was stirredfor 3 hours at room temperature. The product was filtered and the cakewashed with MTBE (50 mL). The dried product (6.4 g) was sampled for wt %assay (92.2 wt %) and HPLC A % (100 A %).

A 1.0 L Buchi hydrogenation vessel equipped with an overhead stirrer,ballast tank, thermocouple, and nitrogen/hydrogen inlet was purged withnitrogen for several minutes. The protected amino-hydroxy amide (49.9 g,0.156 mol, prepared as described above), and 20% Pd(OH)₂ on carbon (2.85g, 0.002 mol, 50% water by weight) were charged to the vessel followedby 700 mL of MeOH. The mixture was agitated at 40° C. until the startingmaterial dissolved (approximately 15 minutes). The vessel and ballasttank were purged 2 times to 40 psig with nitrogen, vented to atmosphericpressure with nitrogen, and pressurized to 40 psig with hydrogen 2times, venting to atmosphere each time. The ballast tank was finallypressurized to 400 psig and the vessel was pressurized to 30 psig viathe ballast tank. The hydrogenation vessel was held at 40° C. and 30psig hydrogen (by regulation via ballast tank) for 2 hours. The vesselwas vented to atmospheric pressure with nitrogen and the slurry wassampled for HPLC analysis for residual starting material (1.8%;limit=0.5% both diastereomers). The vessel was re-purged andre-pressurized to 30 psig with hydrogen and held at 40° C. foradditional 30 minutes. The vessel was vented to atmospheric pressurewith nitrogen and a sample of the slurry was submitted for HPLC analysisfor residual amino-amide (1.1%; limit=0.5% both diastereomers). Thevessel was re-purged and re-pressurized with hydrogen and held at 40° C.for an additional 40 min. The vessel was vented to atmospheric pressureand held overnight under a nitrogen atmosphere.

A sample was submitted for HPLC analysis for residual protectedamino-hydroxy amide (none detected; limit ≦0.5% both diastereomers). Aportion of the product crystallized out of solution during the overnightstir and an additional 300 mL of MeOH was added to dissolve the product.The slurry was warmed to 45° C. to assure dissolution, then filteredover a bed of Celite® at 45° C. The wet filter cake was rinsed with MeOH(250 mL) and the filtrate was distilled at atmospheric pressure to avolume of approximately 150 mL. Ethyl acetate (300 mL) was added anddistillation was continued at atmospheric pressure, again to a volume of150 mL. This procedure was repeated twice more. Heptane (150 mL) wasadded to the flask at 75° C. and the contents were cooled to roomtemperature and ultimately to 5° C. in an ice/water bath. Thecrystallized product was collected, the wet cake was washed with heptane(75 mL) and dried at 40° C. under reduced pressure overnight. The freeamino-amide was isolated as an off-white solid (21.2 g, 0.114 mol, 73.1%yield) with an HPLC purity of 98.5 A % and a wt/wt assay of 94.2 wt %.

Example 1 N-t-butyloxycarbonyl-3-azabicyclo[3.3.0]octane (6)

Method 1

To a 2 L 3-necked round-bottom flask under nitrogen fitted with amechanical stirrer, a 500 mL addition funnel, and a thermometer wascharged 3-azabicyclo[3.3.0]nonane hydrochloride (100 g, 0.677 mol),potassium carbonate (187 g, 1.35 mol), t-butyl methyl ether (220 mL) andwater (160 mL), with stirring. The mixture was cooled to 14-16° C. In aseparate 500 mL erylenmeyer flask was charged Boc₂O (di-t-butyldicarbonate) (145 g, 0.644 mol) and t-butyl methyl ether (190 mL). Themixture was stirred until complete dissolution was obtained. Thesolution was poured into the addition funnel and added to the abovereaction mixture, keeping the reaction temperature below 25° C. Water(290 mL) was added to dissolve solids, and the mixture was stirred for10-15 minutes. After separating the lower aqueous phase, the organicphase was washed with 5% aq. NaHSO₄ (twice, 145 mL each), then water(145 mL). The organic phase was concentrated and methyl t-butyl etherwas added (1.3 L) to give a solution of the title compound in t-butylmethyl ether. See, e.g., R. Griot, Helv. Chim. Acta., 42, 67 (1959).

Method 2

A solution of potassium carbonate (187 g, 1.35 mol) in water (160 mL)was added to a mixture of 3-azabicyclo[3.3.0]octane hydrochloride (100g, 0.677 mol) and t-butyl methyl ether (220 mL), and the resultantmixture was cooled to 14-16° C. A solution of Boc₂O (145 g, 0.644 mol)in t-butyl methyl ether (190 mL) was added while maintaining atemperature below 35° C. After the addition, the mixture was stirred for1 hour then filtered. The solids were washed with MTBE (50 mL). Thephases were separated and the organic phase washed with 5% aq. NaHSO₄(twice, 145 mL each) and water (145 mL) and concentrated to 300 mL undervacuum. MTBE (300 mL) was added and the mixture concentrated to removewater to less than 550 ppm. The concentrate was diluted with MTBE (400mL) to provide a solution of the title compound in MTBE.

Example 2rac-2-(t-butoxycarbonyl)octahydrocyclopenta[c]pyrrole-1-carboxylic acid(7)

Method 1

The solution from Example 1, Method 1, was charged to a 5 L 4-neckedflask fitted with a mechanical stirrer, an addition funnel, a ReactIRprobe, and a thermometer. 3,7-Dipropyl-3,7-diazabicyclo[3.3.1]nonane(183 g, 0.88 mol) was charged to the flask. Data collection was startedon the ReactIR instrument, and the solution was cooled to −72 to −75° C.sec-Butyllithium (600 mL, 1.6 M in cyclohexane) was slowly added to thereaction mixture, keeping the reaction temperature below −69° C. Theaddition was monitored with the ReactIR instrument, and the addition wasstopped after the absorbance at 1698 cm⁻¹ had disappeared and theabsorbance at 1654 cm⁻¹ ceased to increase for three consecutive scans(2-minute intervals). The solution was agitated for 3 hours at −75 to−72° C. A 10% mixture of CO₂ in nitrogen was carefully sparged into thereaction mixture, keeping the reaction temperature below −70° C. Thesparge was stopped after the absorbance for CO₂ appeared in the ReactIRspectrum (2350 cm⁻¹). The mixture was warmed to 0-5° C., and a solutionof 30 wt % NaHSO₄ (1.4 L) was added. The mixture was warmed to 22-25° C.and stirred for 30 minutes. The aqueous phase was separated and theorganic phase washed with water (700 mL). The aqueous phase was decantedand the organic phase concentrated to provide the title compound.

Method 2

A solution of 3,7-dipropyl-3,7-diazabicyclo[3.3.1]nonane (183 g, 0.87mol) in MTBE (300 mL) was added to the solution ofN-t-butyloxycarbonyl-3-azabicyclo[3.3.0]octane from Example 1, Method 2in a flask fitted with a mechanical stirrer, an addition funnel, aReactIR probe, and a thermometer and the mixture was cooled to −75 to−72° C. A solution of sec-butyllithium (510 mL, 1.6 M) was added,keeping the reaction temperature below −70° C., until the absorbance at1698 cm⁻¹ had disappeared and the absorbance at 1654 cm⁻¹ ceased toincrease. The solution was stirred for 3 hours at −75 to −72° C. Thereaction mixture was sparged with 10% CO₂ in N₂ keeping the reactiontemperature below −70° C. The sparge was stopped when the absorbance forCO₂ appears in the ReactIR spectrum (2339 cm⁻¹). The mixture was warmedto 0-5° C. and a solution of 30 wt % NaHSO₄ (1.4 L) was added and themixture was warmed to 22-25° C. then stirred 30 minutes. The phases wereseparated and the aqueous phase was checked to make sure the pH waslower than 3. The organic phase was washed with water (700 mL) thenconcentrated to 300 mL. Ethyl acetate (1.7 L) was added and the mixtureconcentrated to 300 mL twice to give a solution of the title compound inethyl acetate.

Example 3 (S)-1,2,3,4-tetrahydronaphthalen-1-aminium(1S,3aR,6aS)-2-(t-butoxycarbonyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(9a)

Method 1

Ethyl acetate (2.3 L) was added to the residue of Example 2, method 1,and the mixture filtered through a pad of Celite®.(S)-1,2,3,4-tetrahydro-1-naphthylamine (56.7 g, 0.385 mol) was added andthe solution was stirred for 3-4 hours at 22-25° C. The mixture wasfiltered and the solids were rinsed with ethyl acetate (200 mL). Thesolids were dried at 20-30° C. under vacuum for 4 hours to give 99.02 gof product (73% yield, 90% ee by chiral HPLC).

To a 3-necked RBF fitted with a temperature contoller, a mechanicalstirrer, a reflux condenser, and a nitrogen bubbler, was charged the(S)-1,2,3,4-tetrahydro-1-naphthylammonium salt (88.98 g, 0.22 mol),ethyl acetate (712 mL), and 2-propanol (666 mL). The mixture was warmedto 70-75° C. with stirring. The mixture was stirred for 15-30 minutes,then cooled to −5 to −10° C. over 1 hour. The resultant slurry wasfiltered and the solids were rinsed with cold ethyl acetate (180 mL).The solids were dried in vacuo at 35-40° C. to give 7.37 g of a whitesolid (83% yield, 98% ee).

Method 2

The ethyl acetate solution of racemicN-t-butyloxycarbonyl-3-azabicyclo[3.3.0]octane-2-carboxylic acid fromExample 2, Method 2, was added to a solution of(S)-1,2,3,4-tetrahydro-1-naphthylamine (56.7 g, 0.385 mol) in ethylacetate (300 mL). The mixture was stirred for 3-4 hours at 22-25° C.,then filtered, and the solids washed with ethyl acetate (200 mL). Theproduct was dried at 20-30° C. under vacuum for 4 hours to give thetitle compound (99.02 g, 36% yield) with a 95 to 5 diasteromer ratio.

A mixture of the salt as prepared above (89.0 g), ethyl acetate, and2-propanol was warmed to 70-75° C. until complete dissolution. Themixture was cooled to −5 to −10° C. over two hours and stirred for 3-4hours. The mixture was filtered and the product dried at 35-40° C. togive the title compound (73.7 g, 83% yield, >99.5% ee).

Example 4 (R)-1-phenylethanaminium(1S,3aR,6aS)-2-(t-butoxycarbonyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(9b)

To a solution of racemicN-t-butyloxycarbonyl-3-azabicyclo[3.3.0]octane-2-carboxylic acid (4.66g) in ethyl acetate (100 mL) was added (R)-α-methylbenzylamine (56.7 g)and the solution was stirred for 16 hr at 22-25° C. The mixture wasfiltered and the solids were rinsed with ethyl acetate. The solids weredried at 20-30° C. under vacuum for 4 hours to give 1.47 g of product(43%, 82% ee, 92:8 ratio of exo:endo diastereomers).

Example 5 (1S,3aR,6aS)-t-butyloctahydrocyclopenta[c]pyrrole-1-carboxylate, t-butylester, oxalate

Method 1

A mixture of the (S)-1,2,3,4-tetrahydro-1-naphthylammonium salt preparedas in Example 3, Method 1 (81.7 g, 0.203 mol), t-butyl methyl ether (400mL) and 5% NaHSO₄—H₂O (867 mL, 0.304 mol) was stirred for 30 minutesuntil all solids were dissolved. The organic phase was washed with water(334 mL) then concentrated to 259 mL. t-Butyl methyl ether (334 mL) wasadded and the solution was concentrated again to 259 mL. Theaddition-concentration process was repeated twice more. After the finalconcentration, t-BuOH (158 mL) and dimethylaminopyridine (5.04 g, 41.3mmol) were added. A solution of Boc₂O (67.6 g, 0.31 mol) int-butylmethyl ether (52.0 mL) was added. After stirring for 5 hours atambient temperature, t-butyl methyl ether (158 mL) and 5% aqueousNaHSO₄—H₂O (260 mL) were added and the resultant mixture was stirred.The organic phase was washed with 5% aqueous NaCl (twice, 260 mL each).The organic phase was concentrated to 320 mL, and tetrahydrofuran (320mL) was added. The organic phase was concentrated again to 320 mL, andtetrahydrofuran (320 mL) was added. After concentrating to 320 mL oncemore, methane sulfonic acid (80.1 g, 0.62 mol) was added and thesolution was stirred at ambient temperature for 4.5 hours. The reactionmixture was added to a 30% aqueous solution of K₂CO₃ (571 mL) andstirred. The aqueous phase was extracted with isopropyl acetate (320mL). The combined organic phases were concentrated to 320 mL, andisopropyl acetate (320 mL) was added. The organic solution wasconcentrated again to 320 mL. The organic phase was washed with water(320 mL). Isopropyl acetate (320 mL) was added to the organic phase andthe solution was concentrated to 192 mL. Isopropyl acetate (320 mL) wasadded a second time, and the organic solution was concentrated to 192mL. A solution of oxalic acid (24.1 g, 267 mmol) in isopropyl acetate(448 mL) was added to the organic solution over 2 hours. The mixture wasstirred for 2-4 hours, and the slurry was filtered. The white solidswere rinsed with isopropyl acetate (100 mL) and dried at 35-40° C. undervacuum to yield 52.6 g of the title compound (85% yield).

Method 2

A mixture of (S)-1,2,3,4-tetrahydro-1-naphthylammonium salt as preparedby the method of Example 3, Method 2 (148 g, 0.609 mol), t-butyl methylether (726 mL) and 5% NaHSO₄—H₂O (1.58 L, 0.913 mol) was stirred untilall of the solids had dissolved. The phases were separated and theorganic phase washed with water (726 mL). The organic phase wasconcentrated to about 400 mL. t-Butyl methyl ether (726 mL) was addedand the mixture concentrated to 590 mL. The addition of t-butyl methylether and concentration was repeated to give a final volume of 350 mL.Dimethylaminopyridine (8.42 g, 68.9 mmol) and t-butyl alcohol (260 mL)were added, followed by addition of a solution of Boc₂O (112 g, 0.52mol) in MTBE (88 mL) over 0.5 hour. The mixture was stirred for 5 hoursat 22-25° C. A solution of 5% sodium bisulfate in water was added andthe mixture stirred for 0.5 hour. The organic phase was washed with 5%sodium chloride (twice, 440 mL each) and concentrated to 270 mL.Tetrahydrofuran (540 mL) was added and the mixture concentrated to 270mL; this procedure was repeated twice more to give a final volume of 270mL. Methane sulfonic acid (67 mL) was added over 0.5 hour whilemaintaining a temperature of lower than 30° C. and the mixture stirredat 22-25° C. for 12 hours. The mixture was added to a 30% aqueoussolution of potassium carbonate (478 mL) while maintaining a temperatureof 22-25° C. The mixture was filtered, the phases separated and theaqueous phase extracted with isopropyl acetate (twice, 540 mL each). Theorganic phase was concentrated to 270 mL, then twice evaporated withisopropyl acetate (540 ml) to give a final volume of 540 mL. The organicphase was washed with water (twice, 540 mL), then twice evaporated withisopropyl acetate (320 mL) to give a final volume of 320 mL. Additionalisopropyl acetate (429 mL) was added followed by addition of a solutionof oxalic acid (40.4 g, 0.448 mol) in t-butylmethyl ether (321 mL) over2 hours maintaining a temperature of 22-25° C. The mixture was stirredfor 3 hours at 22-25° C. then filtered. The filter cake was washed withisopropyl acetate (100 mL) and the product dried at 35-40° C. undervacuum to give the title compound as a white solid (88.4 g, 81%).

Example 6 (1S,3aR,6aS)-t-butyl2-((S)-2-(benzyloxycarbonylamino)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(27)

Method 1

A 3-L 3-neck round bottomed flask equipped with an overhead stirrer,condenser, thermocouple, and nitrogen outlet was purged with nitrogenfor several minutes. In a separate flask, sulfuric acid (46.2 mL, 0.867mol) was diluted with 442 mL of water. The solution was allowed to coolslightly. Cbz-L-tert-Leucine dicyclohexylamine salt (330.0 g, 0.739 mol)was charged to the reaction flask. t-Butyl methyl ether (1620 mL) wasadded to the reactor, and the mixture was stirred to suspend the salt.The acid solution prepared above was added to the reactor over about 10minutes, keeping the temperature at 20±5° C. The mixture was stirred atroom temperature for approximately 1 hour, then diluted slowly withwater (455 mL). Agitation was stopped, and the layers were allowed tosettle. The lower (aqueous) phase was withdrawn to provide 1100 mLcolorless solution of pH 1. To the organic phase remaining in the flaskwas charged additional water (200 mL). The mixture was stirred at roomtemperature for approximately 1 hour. Agitation was stopped, and thelayers were allowed to settle. The lower (aqueous) phase was withdrawnto provide 500 mL colorless solution of pH 2. The organic phase washeated to about 35° C., diluted with DMF (300 mL), and concentratedunder reduced pressure to the point at which distillation slowedsignificantly, leaving a concentrate of about 500 mL. The concentratewas transferred without rinsing to a 1-L Schott bottle. The concentrate,a clear colorless solution, weighed 511.6 g. Based on solution assayanalysis and the solution weight, the solution contained 187.2 g (0.706mol) Cbz-L-tert-Leucine.

To a 5-L 4-neck round bottomed flask equipped with an overhead stirrer,thermocouple, addition funnel and nitrogen inlet were charged HOBT.H₂O(103.73 g, 0.678 mol, 1.20 molar eq.), EDC.HCl (129.48 g, 0.675 mol,1.20 molar eq.) and DMF (480 mL). The slurry was cooled to 0-5° C. A36.6 wt % solution of the acid of Cbz-L-tert-Leucine in DMF (491.3 g,0.745 mol, 1.32 molar eq.) was added over 47 minutes to the reactionmixture while keeping the temperature at 0-5° C. The reaction mixturewas stirred for 1 hour and 27 minutes. A solution of3-azabicyclo(3.3.0)octane-2-carboxylic acid t-butyl ester in isopropylacetate (28.8 wt %, 414.3 g, 0.564 mol) was added over 53 minutes whilekeeping the reaction temperature at 0-5.1° C. The reaction mixture waswarmed to 20±5° C. over about 1 hour. 4-Methylmorpholine (34.29 g, 0.339mol, 0.60 molar eq.) was added over 5 minutes. The reaction mixture wasagitated for 16 hours then isopropyl acetate (980 mL) was added to thereaction solution. A solution of histamine-2HCl (41.58 g, 0.226 mol,0.40 molar eq.) in water (53.02 g) was added to the reaction mixturewithin 4 minutes, followed by 4-methylmorpholine (45.69 g, 0.45 mol,0.80 molar eq.). The reaction mixture was sampled after 3.5 hours. Water(758 mL) was added, the mixture stirred for about 20 minutes, thenallowed to settle for 11 minutes. The phases were separated. The aqueousphase was extracted with isopropyl acetate (716 mL) and the organicphases were combined. 1N aq. HCl was prepared by adding 37 wt %hydrochloric acid (128.3 mL) to water (1435 ml). The organic phase waswashed for about 20 minutes with the 1N hydrochloric acid. A 10 wt % aq.K₂CO₃ solution was prepared by dissolving K₂CO₃ (171 g, 1.23 mol, 2.19molar eq.) in water (1540 mL). The organic phase was washed with the 10wt % aq. K₂CO₃ solution for about 20 minutes. The final clear, veryslightly yellow organic solution, weighing 1862.1 g, was sampled andsubmitted for solution assay. Based on the solution assay and the weightof the solution, the solution contained 238.3 g (0.520 mol) of productof the title compound.

¹H NMR (DMSO-d₆, 500 MHz): δ 7.37 ppm (5H, s), 7.25-7.33 ppm (1H, m),5.03 ppm (2H, s), 4.17 ppm (1H, d), 3.98 ppm (1H, d), 3.67-3.75 ppm (2H,m), 2.62-2.74 ppm (1H, m), 2.48-2.56 ppm (1H, m), 1.72-1.89 ppm (2H, m),1.60-1.69 ppm (1H, m), 1.45-1.58 ppm (2H, m), 1.38 ppm (9H, s),1.36-1.42 ppm (1H, m), 0.97 ppm (9H, s).

Method 2

A solution of potassium carbonate (73.3 g) in water (220 mL) was addedto a suspension of (1S,2S,5R) 3-azabicyclo[3.3.0]octane-2-carboxylic,t-butylester, oxalate (80.0 g) in isopropyl acetate (400 mL) whilemaintaining a temperature of about 20° C. The mixture was stirred for0.5 hour, tha phases separated and the organic phase washed with 25% w/waqueous potassium carbonate (80 mL) to give a solution of the free base.In a separate flask, aqueous sulfuric acid (400 mL, 0.863 M) was addedto a suspension of Cbz-t-leucine dicyclohexylamine salt (118.4 g) int-butylmethyl ether (640 mL) while maintaining a temperature of about20° C. The mixture was stirred for 0.5 hour, the phases separated andthe organic phase washed with water (200 mL). The phase were separatedand N-methylmorpholine (80 mL) was added to the organic phase which wasconcentrated under reduced pressure at 40° C. to 80 mL to give the freeacid as a solution in N-methyl morpholine. This solution was added to amixture of EDC.HCl (50.8 g) HOBt hydrate (40,6 g) in N-methylmorpholine(280 mL) at 0-10° C. The mixture was stirred for 1 hour at about 5° C.The solution of 3-azabicyclo[3.3.0]octane-2-carboxylic, t-butylesterfrom above was added at 0-20° C. followed by N-methylmorpholine (32 mL).The mixture was stirred for 6 hour then diluted with isopropyl acetate(600 mL) followed by 1N HCl (400 mL). After stirring 0.5 hour, thephases were separated and the organic phase washed with 25% w/w aqueouspotassium carbonate (400 mL) and water (80 mL). The mixture was stirredfor about 1 hour and the phases separated to give a solution of thetitle compound in isopropyl acetate.

Method 3

(1S,2S,5R) 3-azabicyclo[3.3.0]octane-2-carboxylic, t-butylester, oxalate(1.0 eq.) was suspended in isopropyl acetate (6 vol.) and a solution ofpotassium carbonate (3.0 eq.) in water (3.5 vol.) was added at 20-25° C.The mixture was stirred for 3 hours then the phases separated. Theorganic phase was washed with water (2 vol.).

Cbz-t-leucine dicyclohexylamine salt (1.05 eq.) was suspended inisopropyl acetate (6 vol.) and sulfuric acid (1.3 eq.) in water (5 vol.)was added at 20-25° C. The mixture was stirred for 30 minutes, thephases separated, and the organic phase washed twice with water (2.5vol. each).

The two solutions from above were combined and then cooled to 0-5° C.HOBt hydrate (1.1 eq.) and EDC (1.1 eq.) were suspended in the mixtureand the mixture stirred for 6 hours. The mixture was washed with water(5 vol.) and the resulting organic phase treated with L-lysine (1 eq.)and N-methylmorpholine (NMM) (2 eq.) at 20-25° C. to destroy excessactivated ester. The mixture was then washed with 5% potassium carbonate(5 vol.), 1N hydrochloric acid (5 vol.), 5% potassium carbonate (5 vol.)and twice with water (5 vol. each) to give a solution of the titlecompound in isopropyl acetate.

Example 7 (1S,3aR,6aS)-t-butyl2-((S)-2-amino-3,3-dimethylbutanoyl)-octahydrocyclopenta[c]pyrrole-1-carboxylate(28)

Method 1

A 1 L Buchi hydrogenator was purged with nitrogen three times. A 307.8 gportion of a 12.8 wt % solution of (1S,3aR,6aS)-t-butyl2-((S)-2-(benzyloxycarbonylamino)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(as prepared by the method of Example 6, Method 1) in isopropyl acetate(39.39 g, 0.086 mol) was charged to the reactor. Isopropyl acetate (100mL) was added to the reactor. A slurry of 50% water and wet 20%Pd(OH)₂/carbon (3.97 g) in isopropyl acetate (168 mL) was prepared andcharged to the reactor and agitation was started. The reactor waspressurized to 30 psig with nitrogen gas and vented down to atmosphericpressure. This was repeated twice. The reactor was pressurized to 30psig with hydrogen and vented down to atmospheric pressure. This wasrepeated twice. The reactor was pressurized to 30 psig with hydrogen andstirred at ambient temperature for 1 hour. The mixture was filteredusing a Buchner funnel with a Whatman # 1 filter paper to removecatalyst. The filter cake was washed with isopropyl acetate (80 mL). Theprocedure was repeated twice more using 617 g and 290.6 g of the 12.8 wt% solution of the starting Cbz compound. The material from the threehydrogenations were combined and distilled under reduced pressure (28″Hg). The resultant solution (468.68 g) was assayed for the titlecompound (23.2%, 98.9% purity).

¹H NMR (DMSO-d₆, 500 MHz): δ 3.96 ppm (1H, d), 3.67 ppm (1H, dd), 3.53ppm (1H, dd), 3.19 ppm (1H, s), 2.66-2.75 ppm (1H, m), 2.49-2.53 ppm(1H, m), 1.75-1.92 ppm (2H, m), 1.66-1.74 ppm (1H, m), 1.48-1.60 ppm(4H, m), 1.38 ppm (9H, s), 1.36-1.42 ppm (1H, m), 0.91 ppm (9H, s)

Method 2

The solution of the Cbz derivative 27 from Example 6, Method 2, wasadded to 20% Pd(OH)₂/water (50%, 12.2 g) in a hydrogenation apparatus.The apparatus was pressurized to 30 psi with hydrogen then stirred for 2hr at about 20° C. The mixture was filtered to remove the catalyst, thefilter cake washed with isopropyl acetate (160 mL). The combinedfiltrates were evaporated with about 4 volumes of heptane at 40° C. 2 to3 times to remove the isopropyl acetate. The resultant slurry was cooledto 0° C., filtered and the product dried under vacuum to give the titlecompound (78.8 g, 98.3% purity).

Method 3

A solution of (1S,3aR,6aS)-t-butyl2-((S)-2-amino-3,3-dimethylbutanoyl)-octahydrocyclopenta[c]pyrrole-1-carboxylatein isopropyl acetate from Example 6, Method 3, was added to 20% Pd(OH)₂(2 wt % loading, 50% wet) and the mixture was hydrogenated at 2 bar and20-25° C. for 2 hours. The catalyst was removed by filtration and washedwith isopropyl acetate (2 vol.). The filtrate was concentrated to 10vol. under reduced pressure at 40° C. to give a solution of the titlecompound in isopropyl acetate.

Example 8 (1S,3aR,6aS)-t-butyl2-((S)-2-((S)-2-(benzyloxycarbonylamino)-2-cyclohexylacetamido)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(30)

Method 1

To a 3 L 3-neck round bottomed flask equipped with an overhead stirrer,thermocouple, addition funnel, nitrogen outlet and ice/water bath wascharged HOBt.H₂O (51.74 g; 0.338 mol, 1.05 molar eq.), EDC.HCl (64.8 g;0.338 mol, 1.05 molar eq.) followed by DMF (197.1 g, 208.8 mL) andagitation was started. The slurry was cooled to 0-5° C., then a solutionof the acid 29 (98.45 g; 0.338 mol, 1.05 molar eq.) in DMF (172.4 g;182.9 mL) was prepared and charged to the addition funnel. This wasadded over about 30 minutes to the batch, maintaining the temperature at0-5° C. Once addition was complete the reaction mixture was agitated at0-5° C. for 2 hours. The solution of the amine 28 in isopropyl acetate(450 g solution; containing 104.4 g of acid 29, 0.322 mol) was chargedto an addition funnel and added drop wise over 1 hour maintaining thetemperature at 0-5° C. Sample analysis indicated incomplete reaction andadditional EDC hydrochloride (3.89 g) was added. After 3 hours, analysisof a sample showed 1.8% amine 28 remained. A slurry of HOBT.H₂O (2.59 g;0.0169 mol), and EDC.HCl (3.24 g; 0.0169 mol) was prepared in DMF (10.44mL) and cooled to 0-5° C. A solution of acid 29 (4.92 g; 0.169 mol) inDMF (10.44 mL) was prepared and added to the slurry of EDC.HCl and HOBTin DMF over 30 minutes, maintaining the reaction temperature at 0-5° C.The mixture was stirred for 1 hour at 0-5° C. then added to the originalmixture maintaining 0-5° C. The mixture was stirred for 14 hours atabout 25° C. A solution of histamine.2HCl (11.84 g; 0.064 mol) in water(8.9 mL) was prepared and added to the reaction mixture over 5-10minutes. A charge of 4-methylmorpholine (13.01 g; 0.129 mol) was addedto the batch over about 10 minutes, maintaining the batch temperature at20±5° C. The reaction mixture was diluted with isopropyl acetate (443mL), followed by water (585 mL). A solution of potassium carbonate (57.8g) in water (585 mL) was added and the mixture was stirred for 0.5 hour.The layers were separated the aqueous layer was extracted twice withisopropyl acetate (twice, 235 mL each). The combined organic phases werewashed with 18% aqueous HCl in water (585 mL), then NaHCO₃ (43.25 g) inwater (585 mL). The layers were separated to give a light yellowsolution of product 30 in isopropyl acetate weighing 1159.3 g (1275 mL)containing 16.0 w/w % 30 in isopropyl acetate.

¹H NMR (DMSO-d₆, 500 MHz): δ 7.74 (1H, d), 7.36 (5H, m), 7.34-7.26 (1H,m), 5.01 (2H, s), 4.51 (1H, d), 4.02 (1H, t), 3.96 (1H, d), 3.73 (1H,m), 3.66 (1H, m), 3.68 (1H, m), 2.53 (1H, m), 1.86-1.76 (2H, m),1.70-1.30 (10H, m), 1.39 (9H, s), 1.15-0.85 (5H, m), 0.96 (9H, s).

Method 2

A solution of Cbz acid 29 (59.62 g) in N-methylpyrrolidone (126 mL) wasadded to a suspension of EDC.HCL (39.23 g) HOBt hydrate (31.34 g) inN-methylpyrrolidone (221 mL) while maintaining a temperature of about 0°C. After the addition, the mixture was stirred for 1.5 hours at about 0°C. A solution of the amine 28 (63.24 g, as prepared in Example 7, Method2) in isopropyl acetate (632 mL) was added to the mixture maintaining atemperature of about 0° C. After the addition the mixture was allowed towarm to room temperature and stirred for 5 hours. A solution ofpotassium carbonate (20.17 g) in water (316 mL) was added whilemaintaining a temperature of about 20° C. The mixture was vigorouslystirred for 0.5 hour. The phases were separated and the organic phasevigorously stirred with potassium carbonate (105.3 g) in water (316 mL).The organic phase was separated and washed with 1N HCl (316 mL), andthen water (158 mL) to give a 12.7% w/w solution of the title compound30 in isopropyl acetate.

Method 3

To a solution of (1S,3aR,6aS)-t-butyl2-((S)-2-amino-3,3-dimethylbutanoyl)-octahydrocyclopenta[c]pyrrole-1-carboxylate(1 eq) in isopropyl acetate (10 vol.) was added NMP (5 vol.) followed byEDC (1.15 eq), HOBT hydrate (1.0 eq) and(S)-2-(benzyloxycarbonylamino)-2-cyclohexylacetic acid (29, 1.05 eq) andthe suspension was stirred at 20-25° C. for 4 hr. The mixture was washedwith 5% potassium carbonate (5 vol.). A mixture of glycine (1 eq), NMM(2 eq) and water (1 vol.) was added and the mixture stirred for 4 hr.The mixture was then washed with 5% potassium carbonate (5 vol.), 1Nhydrochloric acid (5 vol.), 5% potassium carbonate (5 vol.) and twicewith water (5 vol. each) to give a solution of the title compound inisopropyl acetate.

Example 9 (1S,3aR,6aS)-tert-butyl2-((S)-2-((S)-2-amino-2-cyclohexylacetamido)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(31)

Method 1

A 60-gallon hasteloy hydrogenating reactor was charged with a solutionof the Cbz peptide 30 (15.1 kg) in isopropyl acetate (109 kg). Thissolution was reduced under vacuum at 50° C. to 68 L. The mixture wasthen cooled to 25±5° C. and MeOH (15.4 kg) added. This mixture wasdrained into a container and the reactor was dried. To the dried reactorwas charged Pd(OH)₂/C (20%, 1.51 kg). The solution containing the Cbzpeptide 30 was added to the reactor and blanketed with hydrogen (30psi). The reaction was stirred at 20±5° C. and at 150-220 rpm for 2hours. After completion, a slurry of activated carbon (0.97 kg) inisopropyl acetate (6.8 kg) was added batch and the mixture stirred for15 minutes. The mixture was filtered over Celite® (2.0 kg) via Sparklerfilter and through a 0.1-um cartridge filter. The reactor was rinsedwith isopropyl acetate (33.0 kg) and the rinse was combined with thereaction mixture. The system was rinsed additionally with a mixture ofisopropyl acetate (25.6 kg) and MeOH (5.73 kg). The combined organicswere reduced under vacuum at 65° C. to 30 L. The solution was cooled to20-30° C. and heptane added (30.8 kg). Distillation was instituted againand the mixture reduced to 30 L. This procedure was repeated for a totalof 4 heptane additions (as above) and solvent reductions (as above). Themixture was cooled to 0-5° C. and the product filtered and washed withheptane (12.6 kg). The wet solid (14.0 kg) was dried under vacuum at15-20° C. to constant weight to give the title compound (10.17 kg).

¹H NMR (DMSO-d₆, 500 MHz): δ 7.97 (1H, d), 4.49 (1H, d), 3.96 (1H, d),3.76 (1H, m), 3.67 (1H, m), 3.05 (1H, d), 2.70 (1H, m), 2.53 (1H, m),1.87-1.77 (2H, m), 1.7-1.3 (10H, m), 1.39 (9H, s), 1.2-0.85 (5H, m),0.96 (9H, s).

Method 2

The solution of compound 30 from Example 8, Method 1, was added to 50%wet 20 wt % Pd(OH)₂ on carbon (3.16 g) in a pressure reactor. Thereactor was pressurized at 30 psi with hydrogen and the mixture stirredfor about 1 hour. The catalyst was filtered, the filter washed withisopropyl acetate and the combined organics distilled to about 65 mL.The mixture was evaporated with heptane (316 mL) several times untilanalysis indicates <0.5% isopropyl acetate. The resultant slurry isdiluted to about 320 mL then warmed to reflux. The solution was slowlycooled to about 5° C., the suspension stirred for 1 hour then filtered.The filter cake was washed with about 65 mL of heptane and the productdried under vacuum at 30° C. to give the title compound (80.16 g) as awhite solid.

Method 3

The solution of (1S,3aR,6aS)-t-butyl2-((S)-2-((S)-2-(benzyloxycarbonylamino)-2-cyclohexylacetamido)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylatein isopropyl acetate from Example 9, Method 3, was added to 20% Pd(OH)₂(2 wt % loading, 50% wet) and the mixture hydrogenated at 2 bar and20-25° C. for 2 hour. The catalyst was removed by filtration and washedwith isopropyl acetate (1 vol.). The solvent was exchanged bydistillation twice with heptane (8.6 vol.) at reflux. The mixture wascooled to 78° C. over 1 hour, then to 22° C. over 2 hours. After 1 hourat 22° C. the suspension was filtered and the cake washed with heptane(3.2 vol.) and the product dried under vacuum at 30° C. with a nitrogenpurge to give the title compound.

Example 10 (1S,3aR,6aS)-t-butyl2-((S)-2-((S)-2-cyclohexyl-2-(pyrazine-2-carboxamido)acetamido)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylate(33)

Method 1

To a 100 mL round bottomed flask was added pyrazine-2-carboxylic acid 32(1.6070 g, 12.95 mmol) and DMF (4 mL). The slurry was stirred at 20-25°C. Meanwhile, a solution of CDI was prepared by combining CDI (2.1012 g,12.96 mmol, 1 molar eq.) and DMF (8.80 g, 9.3 mL) in a 25 mL flask. Mildheating (30° C.) aided in dissolution. The CDI solution was cooled to20-25° C. and added to the slurry of pyrazine-2-carboxylic acid.Stirring was continued for 1.5 hours to assure complete activation ofthe acid as carbon dioxide was produced as a byproduct. Meanwhile, theamine 31 (5.0002 g, 10.78 mmol) was dissolved in DMF (14.15 g, 15 mL)with mild warming to 30° C. aided in the dissolution of the material.This solution was cooled to 20-25° C. The activated pyrazine solutionwas also cooled to about 15° C. The solution of compound 31 was added tothe activated pyrazine carboxylic acid while maintaining the temperatureat 30° C. for about 1 hour. The solution was allowed to cool to 20-25°C. then added to a solution of potassium carbonate (0.25 g) in water(100 mL) at 0° C. The mixture was filtered and washed with water (fourtimes, 50 mL each). The filter cake was dried under vacuum beginning at20-25° C. and warmed to 30° C. after 24 hours until the cake wasconstant weight to give the title compound (5.99 g).

¹H NMR (DMSO-d₆, 500 MHz): δ 9.19 ppm (1H, d, J=1.3 Hz), 8.90 ppm (1H,d, J=2.5 Hz), 8.76 ppm (1H, dd, J=2.4 Hz, 1.5 Hz), 8.50 ppm (1H, d,J=9.2 Hz), 8.22 ppm (1H, d, J=9.0 Hz), 4.68 ppm (1H, dd, J=9.1 Hz, 6.6Hz), 4.53 ppm (1H, d, J=9.0 Hz), 3.96 ppm (1H, d, J=4.2 Hz), 3.73 ppm(1H, dd, J=10.5 Hz, 7.5 Hz), 3.68 ppm (1H, dd, J=10.6 ppm, 3.4 ppm),2.68-2.74 ppm (1H, m), 2.52-2.58 ppm (1H, m), 1.70-1.88 ppm (3H, m),1.51-1.69 ppm (7H, m), 1.31-1.44 ppm (2H, m), 1.39 ppm (9H, s),1.00-1.19 ppm (4H, m), 0.97 ppm (9H, s), 0.91-0.97 ppm (1H, m).

Method 2

Oxalyl chloride (11.29 mL) was added to a solution ofpyrazine-2-carboxylic acid 32 and N-methylmorpholine (59.28 mL) inmethylene chloride (150 mL) at about 30° C. The mixture was stirred for0.5 hour, then a solution of the amine 31 (50.0 g) in methylene chloride(150 mL) was added at about 30° C. After 0.5 hour, the mixture waswashed with water (250 mL). The aqueous phase was extracted withmethylene chloride (100 mL) to give a solution of the title compound inmethylene chloride which was used directly in the next step (Example 11,Method 2).

Example 11(1S)-2-((S)-2-((S)-2-cyclohexyl-2-(pyrazine-2-carboxamido)acetamido)-3,3-dimethylbutanoyl)octahydrocyclopenta[c]pyrrole-1-carboxylicacid (34)

Method 1

Concentrated HCl (150 g, 0.015 mol, 1.2 molar eq.) was slowly added at0° C. to a stirred solution of the pyrazinyl peptide 33 (50.0 g) informic acid (100.0 g). After 3.3 hours, the reaction mixture was dilutedwith 166.5 g of ice water. Methylene chloride (100 mL) was added and thereaction was stirred for 10 minutes to dissolve the product. The phaseswere separated and the aqueous layer extracted with methylene chloride(100 mL). The combined organic phases were washed with water (75 mL)then concentrated to about ⅓ volume at 50° C., 1 atm. Toluene (100 mL)was added at room temperature and the homogeneous solution wasevaporated under vacuum at ≦56° C. to about ⅓ volume. The mixture wascooled to 20-25° C. as a precipitate formed. Heptane (75 mL) was slowlyadded and the slurry stirred for 10-15 minutes. The slurry was filteredand the filter cake was washed with heptane (50 mL). The solids weredried under vacuum at 20-25° C. to give the title compound (15.19 g).

Method 2

The methylene chloride solution of the starting compound 33 from Example10, Method 2, was cooled to 0-5° C. then concentrated HCl (200 mL) wasadded while maintaining a temperature of <10° C. The mixture was stirredfor 3 hours, then diluted with water (200 mL) while maintaining atemperature of <10° C. The phases were separated and the aqueous phaseextracted with methylene chloride (100 mL). The combined organic phaseswere washed with water (100 mL) and the aqueous wash phase extractedwith methylene chloride. The combined organic extracts were refluxedunder an inverse Dean-Stark trap to azeotrope water. The mixture wasconcentrated by distillation to a minimum volume then diluted withtoluene (500 mL) then concentrated by distillation at atmosphericpressure to 250 mL. The mixture was slowly cooled to 20° C. over about 6hours. The resultant slurry was filtered, the filter cake washed withtoluene (100 mL) then dried at about 45° C. in a vacuum oven to providethe title compound (64.7 g) as a pale yellow powder containing about 17%toluene.

Example 12(1S,3aR,6aS)-2-((S)-2-((S)-2-cyclohexyl-2-(pyrazine-2-carboxamido)acetamido)-3,3-dimethylbutanoyl)-N-((3S)-1-(cyclopropylamino)-2-hydroxy-1-oxohexan-3-yl)octahydrocyclopenta[c]pyrrole-1-carboxamide(35)

Method 1

A 500 mL 3-neck round bottomed flask equipped with an overhead stirrer,condenser, thermocouple, and nitrogen outlet was purged with nitrogenfor several minutes. The peptide-acid 34 (25.0 g, 0.049 mol), EDC-HCl(10.35 g, 0.054 mol, 1.1 molar eq.), and HOBt-H₂O (8.27 g, 0.054 mol,1.1 molar eq.) were charged to the flask followed by 175 mL of methylenechloride. The mixture was stirred at room temperature for 1 hour thenadded over 20 minutes to a suspension of hydroxyamide-amine 18 (11.1 g,0.054 mol, 1.1 molar eq.) in methylene chloride (75 mL) whilemaintaining a temperature below 10° C. Upon complete addition,N-methylmorpholine (5.94 mL, 0.054 mol, 1.1 molar eq.) was added in 2portions. The mixture was allowed to warm to room temperature andstirred for 3 hours. The reaction was quenched by the addition of NaHCO₃(8.0 g) in 200 mL of water. The phases were separated and the organiclayer washed with water (175 mL), 0.5 N aq. HCl (200 mL), water (threetimes, 200 mL each) and saturated NaCl (200 mL) to give a 16% by weightmethylene chloride solution of the title compound 35 of 100 A % purity(molar yield 100%).

Method 2

N-methylmorpholine (38.19 mL, 347.3 mmol) was added to a mixture of thepeptide-acid 34 (100.0 g, 89.2 wt %, 173.7 mmol), HOBt hydrate (26.79 g,87.6 wt %, 173.7 mmol), EDCI (36.62 g, 191.04 mmol), and thehydroxyamide-amine 18 in methylene chloride over 30 minutes whilemaintaining a temperature of 0-5° C. After the addition, the mixture waswarmed to 20° C. and stirred for 5 hours. The mixture was then dilutedwith water (500 mL) and stirred for about 0.5 hour. The phases wereseparated and the organic phase washed with 1N HCl (500 mL), 5 wt %aqueous sodium bicarbonate (500 mL) to give a solution of the titlecompound in methylene chloride, 98.5% AUC purity, 95% solution yield.

Method 3

Peptide acid 34 (1.00 eq.), EDCI (1.10 eq.), HOBt hydrate (1.00 eq.),and hydroxyamine 18.HCl (1.05 eq.) were suspended in CH₂Cl₂ (5 vol.) andthe mixture was cooled to 0-5° C. NMM (2.0 eq) was added over 30-60minutes while maintaining the reaction temperature below 5° C. Thereaction mixture was warmed to 20-25° C. over 30 minutes and stirred foradditional 5 hours. The reaction was washed with water (5 vol.), 1N HCl(5 vol.), and 5 wt % aqueous NaHCO₃ (5 vol.) to provide a solution ofthe title compound in CH₂Cl₂

Example 13(1S,3aR,6aS)-2-((S)-2-((S)-2-cyclohexyl-2-(pyrazine-2-carboxamido)acetamido)-3,3-dimethylbutanoyl)-N-((S)-1-(cyclopropylamino)-1,2-dioxohexan-3-yl)octahydrocyclopenta[c]pyrrole-1-carboxamide(4)

Method 1

A 500 mL 3-neck round bottomed flask equipped with an overhead stirrer,condenser, thermocouple, and nitrogen outlet was purged with nitrogenfor several minutes. A methylene chloride solution of the hydroxyamidepeptide amide 35 (128.64 g, 16-17 wt %, 20.6 g and 30 mmol of 35) inmethylene chloride was added to the reaction flask, followed by theaddition of 15% w/w aq. NaBr (13 mL) and 7.5% w/w aq. NaHCO₃ (52 mL).The solution was cooled to 5±3° C. in an ice bath. TEMPO (0.7 g)dissolved in methylene chloride (3 mL) was added to the reactionmixture. In a separate Erlenmeyer flask, 10-13% NaOCl solution (23.25mL, titer=108 mg/mL, 2.51 g, 33.7 mmol, 1.12 molar eq.) was diluted withwater (70 mL). The NaOCl solution was charged to the reaction mixturevia addition funnel at a rate that maintained the temperature below 8°C. The reaction mixture was allowed to stir at 5±3° C. for 1 hour. Thelayers were separated and the organic layer was quenched with 10% (w/w)aq. Na₂SO₃ (100 mL) and washed with water (100 mL). The organic phasewas reduced to dryness at reduced pressure and the solid triturated withethyl acetate (100 mL) and filtered on a Buchner funnel. The solid wassubmitted for A % analysis (>99 A %). The isolated wet cake weighed 16.6g and the molar yield was 80% (wet). The wet cake was not dried as itwas not deemed necessary for use-test purposes.

Method 2

TEMPO (1.09 g, 6.95 mmol) was added to the methylene chloride solutionof 35 from Example 12, Method 2, followed by a solution of sodiumbicarbonate (21.89 g, 260.5 mmol) in water (400 mL) and the mixturecooled to 0-5° C. A solution of sodium hypochlorite (122.17 g, 11.64 wt%, 191.04 mmol) was added over 2 hours while maintaining a temperatureof 0-5° C. The mixture was stirred for 1 hour at 0-5° C., then thephases separated. The organic phase was washed with water (500 mL), 1 wt% aqueous sodium bisulfite (500 mL) and water (500 mL), then polishfiltered. The mixture was distilled at 38-42° C., 710 mm Hg, to a volumeof about 320 mL. Ethyl acetate (44 mL) was added followed immediately by1.5 g of seed crystals of 4 and the mixture was stirred for 15 minutesat 38-42° C. Ethyl acetate (800 mL) was added over 3 hours whilemaintaining a temperature of 38-42° C. The mixture was then distilled at38-42° C., 200-250 mm Hg, to a volume of about 400 mL. Additional ethylacetate (200 mL) was added over 0.5 hour. The resultant slurry wascooled over 1 hour to 20-25° C. and stirred an additional hour at thesame temperature. The mixture was filtered and the filter cake washedwith ethyl acetate (twice, 300 mL each) and dried under vacuum with anitrogen bleed at 45-55° C. to give the title compound 4 as a whitesolid (102.4 g, 99.7% AUC purity, 85% yield) from the hydroxyamidepeptide amide 35.

Method 3

TEMPO (0.06 eq) was added to the CH₂Cl₂ solution of 35 from Example 12,method 3, and the solution was stirred at 20-25° C. until all TEMPOdissolved. To this solution was added a solution of NaHCO₃ (1.5 eq.) inwater (4 vol.). The resulting biphasic mixture was cooled to 0-5° C.While maintaining the reaction temperature at 0-5° C., a 10-13 wt %NaOCl solution (1.10 eq.) was added over 2-3 hours and the mixturestirred for additional one hour. The layers were separated and theorganic layer was washed at 0-5° C. with H₂O (5 vol.), 1 wt % Na₂SO₃ (5vol.), and H₂O (5 vol.). Glacial acetic acid (0.12 eq.) was added to thesolution of compound 4 in CH₂Cl₂ to stabilize compound 4.

Example 14 Recrystallization of Compound of Formula 4

The solution of Compound 4 from Example 13, Method 3, was filteredthrough Celite, and the filtrate solution was reduced to 3.1-3.3 volumesby vacuum distillation at lower than 20° C. After distillation, thesolution was brought to 38-42° C. before EtOAc (0.80 vol.) was added,followed by the addition of Compound 4 seed (1.5 wt % relative to 34,Example 12). The resulting mixture was stirred for 15 minutes at 38-42°C. EtOAc (8 vol.) was added over 3 hours to this mixture whilemaintaining a temperature of 38-42° C. The total volume of the slurrywas then reduced to 3.9-4.1 volumes by vacuum distillation at 38-42° C.To this mixture was added EtOAc (2 vol.) over 30 minutes whilemaintaining the batch temperature at 38-42° C. The resulting slurry wasthen cooled to 20-25° C. over 1 hour and stirred at 20-25° C. foradditional 1 hour. The slurry was filtered. The filter cake was washedwith EtOAc (twice, 3 vol. each) and dried under vacuum with a nitrogenbleed at 45-55° C. for 6 hours.

To the dried filter cake was added 2.2-2.4 volumes of CH₂Cl₂ to a totalvolume of 3.1-3.3 volumes. The mixture was brought to 38-42° C. to givea homogeneous solution. EtOAc (0.80 vol.) was added, followed by theaddition of Compound 4 seed (1.5 wt % relative to 34, Example 12). Theresulting mixture was stirred for 15 minutes at 38-42° C. EtOAc (8 vol.)was added over 3 hours to this mixture while maintaining a temperatureof 38-42° C. The total volume of the slurry was then reduced to 3.9-4.1volumes by vacuum distillation at 38-42° C. EtOAc (2 vol.) was addedover 30 minutes to this mixture while maintaining the batch temperatureat 38-42° C. The resulting slurry was then cooled to 20-25° C. over 1hour and stirred at 20-25° C. for additional one hour. The slurry wasfiltered and the filter cake was washed with EtOAc (twice, 3 vol. each)and dried under vacuum with a nitrogen bleed at 45-55° C. for 12 hour togive purified Compound 4.

1. A process for preparing a compound of Formula 4

comprising the steps of: i) providing anN-alkoxycarbonyl-3-azabicyclo[3.3.0]octane; ii) forming a 2-anion of theN-alkoxycarbonyl-3-azabicyclo[3.3.0]octane in the presence of achelating agent; iii) treating the anion of step ii) with carbon dioxideto produce a cis-/trans- mixture ofN-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acids; iv)treating the mixture of step iii) with a strong base to produce anessentially pure trans-N-alkoxycarbonyl-octahydrocyclopenta[c]pyrrole-1-carboxylic acid; v)forming a salt with an optically active amine; vi) crystallizing thesalt; vii) esterifying the acid provided in step vi); viii) removing theN-alkoxycarbonyl group to produce(1S,3aR,6aS)-t-butyl-octahydrocyclopenta[c]pyrrole-1-carboxylate,t-butyl ester; ix) reacting the bicyclic aminoester of step viii) with aprotected amino acid of formula 26,

wherein Z is an amine protecting group, in the presence of a couplingreagent, to produce an amide-ester of formula 27;

x) removing the protecting group Z from the amide-ester of step ix) toproduce the amino compound of formula 28;

xi) reacting the amino compound of formula 28 with a protected aminoacid of formula 29

in the presence of a coupling reagent to produce a tripeptide of formula30;

xii) removing the protecting group Z in the tripeptide of Formula 30 toproduce a free amino-tripeptide of formula 31;

xiii) reacting the amino-tripeptide of formula 31 withpyrazine-2-carboxylic acid in the presence of a coupling reagent toproduce an amide-tripeptide ester of formula 33;

xiv) hydrolyzing the ester of the amide-tripeptide ester of formula 33to produce an amide-tripeptide acid of formula 34;

xv) reacting the amide-tripeptide acid of formula 34 with anaminohydroxy-amide of formula 18

in the presence of a coupling reagent to produce a hydroxy-tetrapeptideof formula 35; and

xvi) oxidizing the hydroxy group of formula 35 to produce the compoundof Formula 4;


2. The process of claim 1, wherein the oxidizing reagent used in stepxvi) is sodium hypochlorite and the oxidation is carried out in thepresence of 2,2,6,6-tetramethylpiperidinyloxy free radical (TEMPO). 3.The process of claim 1, wherein the oxidizing reagent used in step xvi)is 1,1-dihydro-1,1,1-triacetoxy-1,2-benzoiodooxol-3(1H)-one.
 4. Theprocess of claim 1, further comprising dissolving the compound ofFormula 4 in an organic solvent to obtain a solution of the compound ofFormula 4, and then adding an acid to the solution.
 5. The process ofclaim 4, wherein the organic solvent is methylene chloride, and the acidis acetic acid.
 6. The process of claim 4, further comprisingconcentrating the solution of the compound of Formula 4 to obtain thecompound in a solid form.